I found an informative post about a related issue that might be of some use to you. Sounds like DHCP or Network Manager may be rewriting your systems-resolved.conf.

https://joshrnoll.com/my-tailscale-dns-woes/

Have you tried deleting /etc/systemd/resolved.conf and restarting the service with systemctl restart systemd-resolved?

Did you undo the reverse path strict filtering your guide suggested?

net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.rp_filter = 1

Above is what the guide suggests to force reverse path strict filtering. Try setting as shown below:

net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.all.rp_filter = 0

You may not be able to do RAID or other redundant/performant arrays with USB. You can definitely achieve a big JBOD array but it will be less resilient and slower than a RAID array. Enclosures often don’t cool as well so heat may degrade your disks faster as well. I did this for a while with some old disks and some $30 HDD toasters. I only put data on there I could afford to lose. I wish there was a standalone hardware RAID solution… like a NAS without the network. That would have a huge draw for hobbyists that don’t want to buy an expensive NAS. I’ve searched for this but haven’t found anything. Message me if you know of such a product! Maybe consider building your own NAS with an old PC. Way cheaper than a prebuilt and fun to build! I had an old Dell Optiplex 990 that is now a 32 TB NAS. Had to get a new case but it’s a decent backup to my Synology.