Hello folks.
Here is another bootimage that I hope could have fixed the RIL crashing issue.
Basically, what I did is that I revert the kernel back to lineage-16.0 branch from rinando and apply my changes on top of it. So this kernel has no lineage-17.1 commits (which I have been cherrypicking los17 commits to our los16 sources all the while). the cpu governor was configured to ondemand, so you should experience better battery life at the cost of having slower performance.
I just consulted rinando and seems like kernel shouldn't be a cause of the RIL issue unless there's upstream source changes related to binder (which imo is unlikely since it's already android 11 now). However who knows if the unrelated is related. So I just go ahead and rework the kernel from a fresh lineage-16.0 branch from i9100.
I seriously don't know what went wrong since I almost reverted all lineage-17.1 changes on my side

Sorry folks, my capability is not enough ._. but I will try my best to resolve this.
So far it's already 9 hours on my side. If the RIL is up for 3 days, we are good to go. This kernel is magisk-patched and there's only magisk patched. You are fine to use even if you don't use magisk.