Everyone here is awesome for ALL the replies. :P Thank you!!
I decided to try a Cloudflared tunnel, but that didn't work out because I can't get the main domain1.com domain to go thru the tunnel... only 'apps', like blog.domain1.com. :P
And, I'm still ironing out how to pass nginx to another local IP on my network; I just haven't gotten it to click yet. All the info needed is right here - I promise to come back when I iron out the setup and post how I managed to do it...
I can figure out how to pass nginx [or apache2, for that matter] to another PORT on the same local IP - I think I have both domains listening on ports 80/443 - and I'll have to change that in order to route the data correctly... let alone getting out to another local IP.
Again appreciate all the info - sometimes I just have to learn a bit more since I have all the documents right here. :P