EDIT: The game has been patched on Steam to fix texture issues: https://store.steampowered.com/news/app/7200/view/3131689217804260004
If you download the game from Steam you might run into some compatibility issues.
You can download the standalone version of the game to avoid all the Steam issues. Log in to the TrackMania Player Page to download the game: https://players.trackmaniaforever.com/
If you don't want to download the standalone version, several Steam Community guides have been made to help fix the game:
White Screen / Online error codes: https://steamcommunity.com/app/7200/discussions/0/3135045355763052773/
How to fix the compatibility issues with Windows 8 & 10: https://steamcommunity.com/sharedfiles/filedetails/?id=448953593
Low Res Textures (SOLVED): https://steamcommunity.com/app/7200/discussions/0/392184522717295932/
Ultimate Fix for wrong VRAM detection (A.K.A Blurry textures): https://steamcommunity.com/sharedfiles/filedetails/?id=2505427657
The TrackMania Competition Patch fixes some other bugs you might encounter. The Competition Patch is also required to submit IL records on TMX: https://donadigo.github.io/tmcp