Welcome to the forum @Niika 
Regarding systemd-boot, you can always try and “recreate” /efi partition as I did here: Dual Boot went south (no more eOS 😭), doesn’t seem to be the same cause, but the remedy might just work (like it did for someone else).
If you’re fine w/ rEFInd and it’s working, you could as well call it a day 
But I guess you should address your booting issue first, most probably Nvidia related looking at your logs:
kernel: [drm:nv_drm_atomic_commit [nvidia_drm]] *ERROR* [nvidia-drm]
having a look here and there might help:
but, hey, idk ¯_ (ツ)_/¯
Cheers !