Which Mac mini models have Thunderbolt 3?

Currently the 2020 M1 Mac min i can't run BootCamp. That may change, but there is no word from Apple.

There are experimental ways to run Windows without BootCamp.

https://duckduckgo.com/?q=windows+on+m1+mac+mini&t=osx&ia=web

2018 Mac mini (Intel), four Thunderbolt 3/USB-C ports. (Still being sold.)

2020 Mac mini (M1), two Thunderbolt 3/USB-C ports.

Yes. The next older is the 2014 Mac mini with Thunderbolt 2.