for me it was just my military rifle addon, disabling it stop the crash (dont need to delete)
but also rarely it wont crash, i test 10 time using same military rifle addon and i didnt crash 2 time out of 10 (the military addon is gone from workshop so i cant send link, it identical to the 42.7mb addon down below though, in the 11 addon i test)

btw for how i test mine military addon + the 11 test down below is
load C7 directly from lobby, local server, friend-only, sv_consistency 0, hard 8 mutation on expert, im alone as zoey with 3 bot, and i dont have any bot improve addon
some test were done by loading the chapter directly from console too

i try remove all addon & disable all addon & disable addon 1 by 1 & putting -heapsize 1572864 +preacache_all_survivors_1 in launch option & put military addon higher or lower priority than the map, all of dat still always crash when i enable my 1 military rifle addon, even when it the only addon i have apart from the 4 silent hill map
my military addon seem fine though, no issue on sound or reload speed in local server, but it have it scope remove, though other military addon still crash without having it scope remove

(fyi my addon is 972mb consist of character + blur remove no smoker smoke + many reskin weapon + some reanimation no skin weapon + script like bhop counter & map progress + admin system + blood color change + color correction + 7 xDR + skybox change + valve missing content fix + hud + vocalizer)

though no mater how many addon i have or even none at all, and crash or no crash
i always get very laggy 5s loading in chapter 7, but the lag is gone after few seconds
lag like everything become very choppy, my fps die, the stat 'in & out' in net_graph spike to 2-3k ( normally it around 70-300), i also always crash during the lag spike part

i test 11 military addon on workshop and i dont see any obvious reason why it crash
cus it both crash/not crash on high or low file size + with or without gun sound
i did try putting the addon higher or lower priority than the map addon, i also did try putting the addon in my addon folder so it instant load or just load from the workshop, still same result
(i dont do mod stuff tho so i have 0 clue about these stuff)

here all the 11 i test (+sound mean have custom gun-fire sound, no mean no crash)
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3127222736 161.44mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2807077581 101.95mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=874742268 77.90mb +sound | no
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2484532474 77.05mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3043607083 42.7mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=251164211 21.61mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=348880029 5.66mb +sound | no
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3274938622 5.04mb +sound | crash
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2972348652 4.19mb | no
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2623654676 1.27mb | no
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2973904332 1.23mb | no

maybe it just the military rifle addon cus all my other weapon addon didnt crash
could be luck but i kinda doubt cus some of my weapon addon have problem like reload speed isnt the same on local server + error in console when shooting, and some are 50mb+

I thank you for comprehensively breaking down the testing on this issue. From what I observed so far is that it's the weapon mods that crash this chapter. I'll be sure to add all those mods to the list as well as mention you.

The reason why you load longer on chapter 7 with poor performance is because it's not optimized. I mean literally at all. I mentioned this before, but I use far z clip for optimization on all other chapters except the 7th and 8th where you can't do that, because they have 2 fog controllers. (day and night) If you do, it will cause visual bugs. Those chapters need traditional way of optimization. I'll get to that eventually, there are also a few bugs that I want to address like spawning under floor on transition to the 4th map and a few other QoL changes. But until then, I'm glad that we finally have some confirmation regarding this issue. I'll be sure to continue redirecting people here if they crash, this was a big help.

The optimization may actually fix the crashing, but I'm not certain. Far Z Clip plane is so effective, because it literally stops rendering everything inside the fog which allows your system to save resources to render things you can actually see. The traditional optimization may work this way, but only if done properly. This will take some time

npp
forgot to say 2 thing that might help
when i load in i test by completely afk, or get the key then go out, or get the key & weapon then go out and shoot + kill + shove infected, or get the key & spawn in military rifle then go out and shoot + kill + shove infected, and sometime i also spin insanely fast for all of dat test (was thinking maybe it could be the reason too, i spin by m_yaw 100 and spin my mouse)
all can crash/no crash

when i disable addon 1 by 1 with military rifle addon enable
most weapon took 0-7 restart to crash
(i restart by using admin addon and cycle through !kill all, !incap all, !restart)
but scout and katana didnt crash after 7 restart, dat was kinda weird cus i thought it might have been scout and katana since it didnt crash when i disable addon 1 by 1
but when i figure out it was military then it almost always crash with military + all my other addon enable, and 0 crash with military disable, soo im not sure if my katana & scout affect anything
mine scout addon katana + 2nd katana

I disabled the military sniper replacer I was using and that fixed it, but I would crash if I turned around after spawning in. If I walked straight forward to grab the key first I could play the level just fine (aside from dying horribly in the otherworld). It also seemed to be fine if I died and retried. However the other military sniper replacements I tried would crash no matter what. It seems like every other type of mod works fine including Left 4 Bots 2.

Works if I grab the key before looking around
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=127092345

Always crashes
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=3249626034
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2947445382