Fresh install of Arch

Restore a backup with timeshift

mount the partitions

mount /dev/nvme0n1p2 /mnt
mount /dev/nvme0n1p3 /mnt/home

Chroot

arch-chroot /mnt /bin/bash

restore

timeshift --restore

Select snapshot:

0 > 2021-07-08_20-00-02 D W
1 > 2021-07-09_21-00-02 D
2 > 2021-07-10_00-00-37 O
3 > 2021-07-10_15-00-35 O
4 > 2021-07-10_16-48-33 O
5 > 2021-07-11_10-00-02 D
6 > 2021-07-11_12-23-57 O

I will take the last one:
6
Re-install GRUB2 bootloader?
N
Do you know the risk ?
Y
And now you have to wait until it's done.

if you see Restore completed you can continue.

unmount & reboot

exit
umount -R /mnt
reboot