Alright, after playing 0.7.2 with and without the scrappy mod, and unpacking and looking over the code, I'll have to say this:
The game is getting way heavier than Renpy can handle. Lagspikes even without autosaves are a lot more frequent than 0.6.1.
And I have a top of the line gaming computer, i9 10th gen, 2080 super, 3 separate SSDs, all top grade, the works.
I'm watching CPU and GPU usage during gameplay, and there's nothing spiking. This is all code bottlenecking. ( Also a data scientist very proficient in Python, pyspark and the like, and Renpy is not that off for me to analyze)
DPC is coding extremely variable heavy. And the callouts with all the conditional clauses he's using is bottlenecking Renpy's already slower response times.
This is why even indie devs use stuff like Unreal engine to make some VNs.
DPC's lack of OOP ( object oriented programming for the uninitiated) coding is going to make this game unbearably slow and crash prone by the time he hits episode 10 at this rate.
I'd set aside a whole month, hire a proficient coder and rework the entire codebase for his Steam season 2 release after Episode 8 release.
Comments welcome. Just wanted to add my two cents in. Wish he allowed Steam customers to comment directly on his discord, because I could point out where he was specifically going wrong even.
Edit note: There are a total of 13 separate variables he included just to make scrappy used saves incompatible in his releases. While, sure, by themselves don't mean much in computing expense, it's just an indicator of his tech debt skyrocketing so fast with each release.