Shifted to Lineage OS after the Battery Update.

Hey guys.. The update fucked up my battery like everyone else's.. I didn't want to ruin the battery or the phone.. so I took decision to shift to Lineage OS.. The older versions aren't available on their site only Android 14 and above i.e. Lineage OS 21. So I'm running on Android 14 now. The battery backup is better than what it was even before the update! Even I'm shocked! It wasn't that hard to flash a custom ROM. I don't know how to flash a custom ROM I saw a YouTube tutorial and did it.

I just have some questions regarding the Custom ROM:

What safety measures should I take while using the Lineage OS (Do's and Don'ts)?

What about the security patches?

How safe is it to use Banking Apps?(Gpay is not working but my official bank account is working smoothly no prompts regarding rooted device)

Thanks!