Lagging with Modpack

Bug on java edition when running a forge modpack i made for 1.20.1 where the game lags excessively. Checked the output log and i got a lot of "Can't keep up! is the server overloaded? running [number]m or lagging [number]ticks behind" although i was in a singleplayer world, not a server. i didn't see any issues or conflicts between mods and all were up to date. Additionally, i allocated the maximum amount of RAM possible. Note that the modpack version is 1.20.1, not 1.20.4 so the game always runs at 1.20.1