Migrate from systemd boot to GRUB2 (Luks on LVM2)

So I decided to give systemd boot a try and I’m regretting it.

My first warning sign was Timeshift not working correctly. I enabled the cronie.service and that has so far only gotten me like three automated Boot backups out of everything that’s scheduled - something was clearly not working correctly.

I did some digging and it seems like GRUB2 is the only bootloader supported by Timeshift, which might explain the behavior… I also saw a lot of comments from people on EndeavourOS having difficulties after doing a Timeshift restore. I haven’t encountered this problem yet but I feel that is going to cause me big problems one day when I am really not in the mood for more problems.

I thought a workaround might make this bootloader salvageable, but then I found out apparently systemd boot can’t boot to other drives. I want to dual boot Ubuntu from another disk (this is next on my to-do list), so it’s clear to me that trying this bootloader was a big mistake.

I wish I understood these massive drawbacks during installation, but it’s too late for that now. I don’t want to reinstall. I’ve been configuring and personalizing for weeks before realizing this will be an issue… So, how can I migrate to GRUB2? Do I have to take any special steps if my root & home LVM is encrypted?

Omitting other encrypted partitions, my installation structure is like this:
nvme0n1 259:5 0 3.6T 0 disk
nvme0n1p2 259:6 0 2G 0 part /efi
nvme0n1p3 259:7 0 68G 0 part [SWAP]
nvme0n1p4 259:8 0 3.6T 0 part (this is the luks LVM below)
luks-4bee5dd8-d5bd-4e44-bc3d-672534df977c 253:6 0 3.6T 0 crypt
vg–endeavourOS-home 253:7 0 3T 0 lvm /home
vg–endeavourOS-root 253:8 0 584G 0 lvm /