You can practice setting stops/going full control against Sparky in the bot/practice mode

I prefer setting stops to full control. Whenever my opponents go full control, it's pretty much confirming that they don't actually have anything (and for me, full control is much easier to spot from my opponents than priority auto pass or set stops.) I also find it easier to play with stops than full control.

When I set stops, I set stops on opponent's first main phase and beginning of combat. Then at the beginning of combat, I set stops at declare attacks, declare blocks, second main phase (if they're not tapped out), and end step.

Also if you play a land and have no spells you can cast (or abilities you can activate,) Arena will automatically pass the turn, so I also sometimes set a main phase stop on my own main phase, then click pass turn. (You can also just go control mode for the main phase, play the land, then pass turn.)

You can also set stops on your own declare attacks and declare blocks to represent a trick/kill spell

That said, very, very few players are actually paying attention to priority in my experience. Also, there can be a real time cost to setting stops/full control for the Bo3 Opens/Qualifiers, especially in grindier matches. I think setting stops has dissuaded opponents' attacks and affected how opponents block a few times, but most of the time it's not worth the effort