I really like these studios and their games, Keen and CD Projekt, but both have blanket bans in their licensing. I mention them only because I am familiar with them and they are not unique.
From CDPR
[No technical misuse] Don’t modify, merge, distribute, translate, reverse engineer, or attempt to obtain or use source code of, decompile, or disassemble our Games and/or Services, unless we expressly allow that in this Agreement or it is allowed by the applicable law.
[No hacking or cheating] Don’t create, use, make available and/or distribute cheats. By cheats we mean things like exploits, automation software, robots, bots, hacks, spiders, spyware, scripts, trainers, extraction tools, or other software that interact with or affect our Games and/or Services in any way (including any unauthorised third party programs that collect information about our Games and/or Services by reading areas of memory used by our Games and/or Services to store information).
As a modder, I have to partially decompile the executable to see what is going on and how to make adjustments. Often its a tree among the forest, laser focus thing where I am stepping along in an attached debugger. Alternatively Cyberpunk 2077 has mods designed to support other mods (eg CyberEngine) which is hooked into at least a third of the game logic.
While I am not afraid of being financially ruined by the current operators of these studios, things change and sometimes not for the best.
There has to be a better alternative where Game studios don’t hold the legal sword of diamocles over a modder.