I was going to mention that I experience a different problem with Godot – mine doesn't lag; instead, it freezes after about four hours of usage. However, your situation might be distinct. Dr. Stonedahl suggested trying Godot version 3.5 if the crashes persist, but given that you've tested it on three computers, I doubt this is the root cause. I would recommend investigating the code, as there could be a possibility of running an infinite call or loop.