Okay this is pretty cool. Thanks to the magic of Wireguard, I now have bidirectional connectivity between my home network and this remote server rack! Devices on either side don't need to run wireguard and don't need any special configuration, and can reach hosts on both sides. I haven't found any documentation on configuring this, so I'm going to have to write this up soon! Shoutout to @mitch for figuring out the missing piece to make this work!
@aaronpk My very limited network knowledge I gathered messing around with network namespaces leads me to think "it's just a bridge, no?". Am I right in a sense? Where am I wrong? Will read the write-up.