Stuck with bricked OS
Eventually solved it...
The Galaxy Watch thing + the Netflix thing were solved with this combination(not sure which of these steps solved it):

Installed MagiskHide Props Config module and blocked the following using Magisk Hide:

Galaxy Watch Plugin(all)
Galaxy Wearable(all)
Google Play Games
Google Play Music
Google Play Services for AR
Google Services Framework
NFC
Samsung Health
Wearable Manager Installer
Google Play services(com.google.android.gms and com.google.android.gms.unstable only)
Google Play Store(all except com.android.vending)


Ran these commands as root:


mount -w -o remount /vendor
cp --preserve=all /vendor/etc/vintf/manifest.xml /vendor/etc/vintf/manifest.xml.bak
sed -i /`grep wsm /vendor/etc/vintf/manifest.xml|sed 's@/@\\\/@'|sed 's@&gt;@\\&gt;@g'|sed 's@&lt;@\\&lt;@g'|tr -d ' '`/,/'&lt;hal format=&quot;hidl&quot;&gt;'/d /vendor/etc/vintf/manifest.xml
mount -r -o remount /vendor


Installed Bluetooth Library Patcher module

Now the GBWhatsapp Mini problem. For some reason it required that Install unknown apps permission would be allowed for it.
Now everything works fine.