Agreed. Element X and sliding sync don't support sso yet, so I've been unable to try them :/
Once those are added I'll be excited to give them a shot.
I currently use matrix and element with many bridges as my sole chat interface and it's very slow. So I look forward to speed improvements.
This. Helm charts and renovate. The (frequently) included release notes help ease upgrades. If the charts / apps you deploy publish good release notes, you will get them in the renovate, easing your mind when upgrading.
It's not perfect. Some don't publish release notes, or the release notes only include the chart changes and not app changes. But if provided, there's a link to the source to double check.
Also having something like ArgoCD that allows you to preview chart changes before syncing is very useful.