turbo trainer on wtb 27.5 sx19 wheel is it possible
Trainers are hard on bikes and on tyres/tires.  You want a cheap hard-wearing tyre for the rear.   Grip and tread are mostly irrelevant, and even a mostly worn tyre is probably fine.  Get every bit of usage out of the rubber.

Some people choose to have a spare rear wheel to swap out for convenience, because that's less work than swapping the tyre.

Others have a dedicated trainer bike permanently mounted in the trainer. Sometimes they even have no front wheel, purely for space saving.

Aside - Consider setting up a fan to replicate the passage of air.  Its hot and sweaty working on a trainer without airflow.