I passed safety net now with Magisk/Zygisk. I realized that I had just forgotten to clear all data of Google Play Services and the Google Play Store. After clearing all data of these apps I additionally installed Universal safety net fix 2.4.0. in Magisk. Bingo!
Is it possible to enable split screen? Freeform is awkward and hard to get two screens side by side. Also, I sometimes get "Trebuchet keeps stopping" messages (when trying to split for example). Is it possible to install another launcher and disable Trebuchet?
Thank you. Animations had been turned off. I turned them back on and split works and trebuchet doesn't crash any more,I've never tried to use split screen before. I just checked on a different device with LOS 19.1 (my T710 isn't on 19.1 at present), and the split screen option wasn't showing. Then I found this LOS issue https://gitlab.com/LineageOS/issues/android/-/issues/4668, and re-enabled animations (which I had turned off at some stage). "Split top" is now available and seems to work.
So ... if you have animations turned off, try turning them back on.
You can certainly install and use another launcher, but probably can't disable Trebuchet (that option isn't present on the LOS 19.1 device mentioned above).
Try installing another launcher and making it the default home app, and see how that goes.
Some Gapps packages can remove default LOS system apps like Trebuchet and install another app as a system app in their place. You probably need to do a clean install to achieve this.
Would there be any reason to install later versions of NikGapps when the older one works?
If you're happy with 18.1, just stay with that unless you need a feature that's only in Android 13.
@Kyrat - does VLC audio work otherwise, eg to play music? If not, you probably have the same problem as I came across with some versions of VLC. There's no audio output at all with VLC's default audio output method, AudioTrack. Changing that to OpenSL ES fixed the problem for me.