Looking back, I started having crashes in 5T/17.1 recently after some OTA updates and messing around with Magisk: that made me move to total clean install with this 18.1. That fixed those reboots: I could easily trigger these 17.1 crashes by toggling Wifi & 4G_Data: it would crash imm. and start the lineageos boot logo&sequence. After few secs it would be back again. So it did not go via the bootloader at all. Strange. I disliked this trigger happy situation and totally wiped the phone, updated TWRP and installed 18.1. That fixed it. So, also in this/your case, I would go for a fresh and clean install (incl format data). Takes me 1 hour, using SwiftBackup to get it all back up&running (incl registering with banking apps and such). But this is just me, what I would do.In general this ROM works really well. Many thanks to the developers!
I observed 2 issues (OnePlus 5T):
1) Random phone freezes (like once within 1-2 weeks) - hard shut off and reboot helps (I got no data restrictions)