My office has an "unreliable" ISP, that sometimes goes down for a day or more at a time. I have no better ISP choices, so I have to live with it.
My plan was to get a 'travel router' to connected a 4G wireless hotspot to the Mikrotik, thinking I would literally swap the WAN cable from the ISPs modem to the travel router. Unfortunately, the travel router limits the supported IP/Subnets to 192.168, 172., and 10.0. subnets, which don't overlap the static IP that my ISP provides. Maybe I picked the wrong travel router?
That means I have to create a second WAN on the Mikrotik or reconfigure the WAN each time the switch happens. It looks like "fallover" is pretty complex for a old soul to understand, let alone implement. Most of the videos I've found are in Slovakian(?) or in such a heavy accent that they are very difficult to follow. This is my wife's small office, and I'm a long retired hardware engineer that works on an as needed volunteer basis. I want my wife to be able to accomplish the switchover by just turning on her hotspot, since I'm generally not in the office.
I'm hoping that the fact that since I don't really want load balancing, rather just a backup path that only needs to fallover one direction, it might be simpler than typical scenarios?
I've used WebFig for everything I've done up to now, which is to do basic setup and create VPN/L2TP remote access. It's been working fine for months except for this ISP problem. The VPN access can fail when I'm in emergency mode.
One other thing is that the "production" ISP is about 1/4 the speed of the 4G connection, if that complicates things. It's SO FRUSTRATING to see two fiber optic cable vendors hanging on the pole outside the office, and not be able to get fiber...