It's a pretty complicated question and maybe one of the most important ones. I edit and create my own personal generators based on others and code from other AIs. ChatGPT has got pretty decent at writing generators and features for the pages I want or copy/pasting/merging them into my generators.

Ai character chat has the "lorebook" section where you can maybe do something similar to what you are asking about but its kinda mysterious exactly how the AI reads and uses the text there. AI RPG does still warns you that your overview is long and memory will be reduced but I do think that the newer model and future models have larger context and tokens etc. so they don't lose focus as quickly anymore. in fact I think some of the older "summary" stuff is outdated and causes more issues than it helps now, actually causing the AI to "forget" faster. I have plenty of issues with the current AI but context and memory are actually pretty decent for me so far.

So the memory isn't about taking up too much space on a server, its about how much text/stuff the AI has to do each time you press generate. in my and some of the other more complex generators, there are lots of text boxes, character trackers, stat trackers etc. etc. and all the more of that stuff there is the more the AI reads before each gen. the story itself is one of those, it reads the ever growing story each time. I think that its capable of reading a decent sized story and keeping up now but the "summaries" and past methods had to try to do some funkyness to help the AIs lower context. I don't use them anymore and the AI was never that good at writing its own summaries or memories anyway without user curation.

I'm rambling but basically I am saying that I am still looking for the answer myself. You can't really change the AI much but you CAN change everything around the AI with perchance and write whatever you want. I can't code either but I am decent at prompting so getting AI to write for Perchance works pretty well for me, maybe you can create something like what you want or modify the lorebook idea from character AI.