If you care about your Tanking SR and give a tiny bit of care for your team mates

Well I suppose he’s playable because it’s the beta season and:

“Players can earn Competitive Points similar to other competitive mini seasons and qualify for Top 500 Leaderboards during the beta season. However, beta season stats will only be available for a limited time and will not count toward a player’s permanent Competitive Season stats.”

https://news.blizzard.com/en-us/overwatch/23060961/introducing-role-queue

In theory that means anything you do now doesn’t really matter as the only permanent thing should be the gold weapon points you get from playing.

It might also be affecting your MMR as off-seasons used to do but… can’t really know without an official statement.

And this is the problem.

The only thing you can practice outside of comp are basic mechanics.
Role Queue beta is at least better than regular comp, as it sounds like the stats from this season will neither be considered when RQ Beta ends nor saved on your profile.