market of LTE devices is shrinking fast, LTE back then had a few USB sticks for around 30-50€ to offer:
Huawei e3372x-xxx (x = placeholder) was once common in the forum, but there are many subrevisions, and several of them require fiddling, before it works, e.g.
(and some subversions don‘t seem to work, better search the forum, before you buy a specific subversion)
Alcatel ik40(v) was once easy to use with OpenWRT, as there was only a single variant to buy, so you knew ahead that it would work. But even in 2nd hand market, it is getting rare now. I got one around 3 years ago, and even back then, market choice was already low.
Consumer market seems to have been
- usb sticks during the early LTE era, which manufacturers were said to stop producing (claiming less and less demand for USB sticks)
- laptops with m2 mobile slots (with the above mentioned still really expensive m2 cards)
- mobile clunky plastic wifi routers with integrated lte/5g modem (all of which have proprietary firmware). If you are willing to connect via Wifi to a clunky ugly plastic device with proprietary firmware, Amazon is for sure happily waiting for you.