Can confirm that MitID will run on Lineage 18.1 after the following:
Install Magisk (I got the 24.3 version) plus the following Magisk modules: MagiskHide Props Config, Universal Safetynet Fix (reboot every time asked to - which is a lot of times)
In Magisk settings enable Zygisk and Enforce DenyList
In Configure DenyList select all Google play related services .
Install MitID app from Play store (don’t open it yet - if you do you must clear the apps cache and storage - under settings and apps)
Add MitId to Magisk DenyList
Edit the file build.prop (I use the app BuildPropEditor from google play)
change the following strings "dev-keys"or “test-keys” to “release-keys”, “userdebug” to “user” and “lineage” to something else fx linage
save and reboot and open the MitId app.
Oddly enough it appears the developers specifically chose to target lineage. First time I missed one instance of lineage in build.props and it still would not run. Seems they are more comfortable with your phone being controlled by some chinese or US company than from the user himself. MitId even will not run after the phone passes safety net tests and google pay works if it finds just one string that says lineage. Really odd priorities if you ask me, and rather amateurish in implementation.
Wish I could just continue with NemID, I am not exactly impressed with MitId or the competence of the developers.
Anyway here you go. Maybe not all these steps are needed, (hopefully someone will test and we can reduce to minimum) but if done it does run.