I have now tried every mod that "forces" medieval tier as being the highest, but none of them seem to work 100%

It is pretty hard to figure out if the issues are caused by mod conflicts, so I thought I would share what I have experienced.

Experiencing issues with Rim Cuisine Bottling and Booze, this mod does not like the "drug settings" if you start a new playthrough with that mod enabled from the beginning. Adding the Rim Cuisine mod later is possible though, but I am worried it might cause issues in an extended playthrough.

Another, much bigger issue, is that this mod doesn't completely remove everything that is higher tier than medieval. I have had people spawn in from shuttle crash (mod that adds more events), and they sometimes spawn with higher tier stuff. Worst part, you cannot move, burn or do anything with those items due to how this mod works.

The biggest issue I experienced was that quest rewards still provide the higher tier rewards, but then this mod removes them after they spawn, so the game then generates a bunch of item stash quests and bandit camps with a 0$ value reward.