Okay forgive the long op but I figured some context would help and I'm terrible at cutting text down. Just skim the first and last four-ish paragraphs for the basics:

So recently I've been wanting to play Starbound again. And I still remembered why I stopped playing in the first place; that being mod conflicts. Although specifically the ones that just break the quickbar button from Quickbar Mini/Stardust Lite/Stardust Core etc. making it show just the normal matter manipulator upgrade menu instead.

So I set about going through my previous modlist in chunks to try and pinpoint the culprit. After a little while I eventually got to a chunk that borked it and went filtering through the mods I had so far. After several days, I had discovered that the culprit appears to be the Spawnable Item Pack.

Last time I tried to resolve this issue I came to the same result and asked the mod authors -the same ones that made both SIP and Quickbar- for help, with log and all. Silver assisted me as much as they could and from what I can remember eventually came to the conclusion that I had so many mods in there that it was impossible to tell. (But their best guess was that it was SIP conflicting with another mod.)

Learning from that, I stripped it all down to exactly 50 mods. ( For the most part additional hair and color options in character creation, texture edits, or things I consider a vital bare-necessity.)

And when narrowing it down to these mods, I tried to make sure that zero out of 47 broke the quickbar on it's own. The other three were the quickbar itself, the quickbar unlocker, and eventually SIP. I was also fairly certain that none of these would affect anything that either touches to function. After moving all my previous characters and worlds to a separate folder, I went to test it.

But the problem still occurs, and SIP still seems to break it. I uninstall SIP, quickbar works fine, I reinstall it, it is broken. Unless I've missed something, not one of these other mods seem to change the result and I'm at a loss. I've gotten as far as I can trying to figure this out on my own, for the 3rd time in a row over the past few years or so.

So now I'm gonna just post this here, cross my fingers and hope that someone knows something that can help.

• The log: https://pastebin.com/1tXK6GSc
  
• The 50 mods in question: https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2903207445

Just a note - Using a different version of quickbar (ie the now deprecated original vs the ones that come with Stardust Core or Lite) still has the same result.