Not bad advices. Especially about NPC - these bastards eat a lot of memory
The only game l have played that is really bad optimized is Yandere simulator with its AI along other things. Because even dropping all settings and having draw distance be 20 meters, the AI surely does all the damage.
also other games(aside Unity) surely have the AI being the heavy dealer to performance loss.
Other games like Artificial academy 2, l have many NPCs(24) and the game lags(low FpS), slowing the process when the 3D model loads when trying to converse. Same In their Summer Scramble (lesser AA2 but summer vacation). But when l only have few characters around, it is considerably lighter and smoother
That's my theory, what l am saying is, by feeling and experience, l can see how heavy the AI can be as a problem.
The problem is how, can someone can efficiently make the AI less to be a burden. More efficient scripts? Without looking at numbers, it is hard to gauge the situation.
Maybe you could ask ChatGPT about this problem or in forums(unity, either by looking topics or asking the question yourself).
This whole situation got me interested, l am sure everyone here can learn something, that's why l reply.
I asked the AI
If you want, l can share the public link