So, Tux Kart?

Edit: or more old school, Wacky Wheels (I think I still have a copy somewhere)

In think you are looking for dash dash world on Steam.

Something like Sonic & All-Stars Racing Transformed? It's been quite a while, but I remember having fun with it. It felt like a Mario Kart kinda game

There's the sonic racing series which has a few ports on PC. I haven't played them on PC, but I've played them on the switch and they're pretty Mario kart-ish both in playstyle and mascot racer charm.

Also you can play as The Heavy.