TBH, this system has been in production since 2016, and the stores essentially can't operate with any downtime... I dispatch updates that are auto-downloaded, and when one of them misfires and I have to spend an hour on remote access, that store's business comes to a halt causing a huge disruption as they transition to paper notes and whiteboards. (The software lets employees track and take ownership of the checkin/checkout and movement of dogs around 30k sqft petcare facilities, each with hundreds of dogs per day... so just the amount of barking when I'm on the phone with these places makes it hilariously difficult to guide people through tech support).

I looked a little bit at Tailscale but assumed it would be too complex for the store employees to manage and would require a lot of hands-on maintenance, and a store-by-store hand holding process which requires scheduling each of them weeks in advance. As it is, the system is secure (local wifi only accessible to employees) and runs even if the store's internet connection goes fully offline... so... I think I'll take your tip and look at it again... the plex model is essentially what I was going for... but I'd be reticent to add any other layers of complexity or anything that could cause downtime.