Hey, I use LOS with Magisk as well.
There is a separate safetynet fix module for magisk you can install. No idea if the module is deprecated or not. Will have to check.
You can use the deny list in magisk to “hide” root access from your banking app.
There is also the option to hide the Magisk app itself. For some reason my banks app was checking for this specifically, and this solved my issues.
Edit: Safetynet fix: https://github.com/kdrag0n/safetynet-fix
This is what I have. Not sure if the project is dead, last update was a year ago it seems.
Aw man, every midrange phone that would be interesting comes with MediaTek SOCs. I should check if the custom rom scene is still dead for phones with MT chips… Do they still withold the sources needed for rom developement?