Got unplayable!?

Hello everyone!
my project has become very slow in a rather inexplicable way.

I state that it is a very light project and above all completely 2d.

I’ve had this problem ever since serializing a list of objects which I later found accumulating instead of replacing. I realized late that this file was quite large!

I did nothing but modify the code and the problem was solved, only now the game has become very slow, especially when I try to load images externally.

Is it possible that maybe it’s a memory / cache problem?

I hope I have explained myself well enough! Excuse the bad English.

Thanks in advance!

Fast Update:
I checked the old code and found no errors