Hello Yasha, shouldn't a ISP (carrier) be "OS agnostic"?
I mean: if I were you I would worry about USB 4G/LTE Dongle OS's compatibility but I would not about ISP (carrier) OS's compatibility...this because (yeah, your YMMV), in general, I would avoid to look for (and, even if found, to consequently use) a USB 4G/LTE Dongle directly connected to my Linux host (AFAIK some Huawei 4G Dongles seem to be globally compatible on Linux, tested on Fedora Workstation), I would *instead* direct my research straight to a 4G/LTE Router that will provide (a) an Ethernet LAN port and, eventually (not necessarily), (b) an embedded WiFi AP.
A lot of headaches will be avoided since a Router is OS agnostic and vice versa.
Have you considered *something similar* to a 4G/LTE Router *like* the
ZyXEL LTE4506-M606? Just plug-in your enabled 4G/LTE carrier's SIM and you should be OK...provided that your carrier provides good 4G/LTE signal on your zone of operation (especially indoor)...it's better than a USB 4G/LTE Dongle IMHO and it's portable too.
I personally use a ZyXEL LTE3301-Q222 (Indoor 4G/LTE Router) in front of my Firewall appliance, so it's used mainly as 4G/LTE Modem (in the LTE 800 MHz band) that does basically only NAT (eventually it can be configured to work in Bridge mode) and it works quite well and it's really stable (better than a copper asynchronous DSL connection, at least here in Italy!).
Maybe I misunderstood your real request, pardon me if I've done.
Kind regards, Davide.