[2020] The game is lagging.

Hey Rubbeldiekatz05,

Thanks for reaching out, welcome to forums and I am sorry to hear about the issue you ran into.

First, just to double-check, does your PC meet the system requirements for Trackmania? If it does, could you have a look at the following article for steps that will allow you to improve in-game performance, therefore give these a go and keep us updated!