somehow the clean up laggs but my pc doesnt go over 80% ram, 40% cpu and 10% gpu.
1. Modern CPUs have multiple cores. typically 4 or 8. indie games tended to be poorly threaded (optimized for more than 1 core) if they even support running on more than 1 core at all (which is rare).
It is entirely possible your 40% actually means "one core at 100%, 1 core at 60%, and 2 cores unused because this game only uses 2 cores"
This is referred to as "single thread performance"
2. The % utilization of ram measures ram quantity used, not ram bus speed usage. It is possible it is maxing out the transfer speed.
3. GPU % measures GPU cores usage (for math). CPU can be thought of like a CPU but with much slower single thread performance, but thousands of cores instead of the standard "4 to 8" cores found in a CPU. Like the ram it is entirely possible that a bus transfer speed is getting capped out. allowing lag without maxing your system resource
4. Sufficiently badly designed scripts or engines can lag even without hitting any of the above, just through mistakes in construction.