I looked at the nanopi r4s and the r6s when I replaced my router. I did consider doing it all myself but in the end settled on the r4s running opwenwrt, I think it took all of 5mins from download to working system. The benefit been the openwrt image has uboot included so only one image need writing, also web interface out of the box
Don't think of it as an installation, it's writing image files to disk. I prefer using gparted or disks when working with partitions. Then use dd for the actual writing as I can quite easily see I've got the right partition from gparted/disks. Got that wrong a couple of times 😅