Recommendations for a SIM router

Recommendations for a SIM router welcomed. Also where to get the SIM from.

Thank you.

I had a Huawei when 4G was fresh new thing in 2014 and it served me well for many a year. In 2019-20 whilst I was temporally renting and in need of decent internet in the big smoke I had a VF GigaCube which was a white labelled Huawei 5G router. Again no complaints. Good solid box.

Your second SIM (actually network) question is VERY much dependent on where you live and the vagaries of the networks in your locality. That unfortunately is something that you will need to test and check for yourself.

This very much also marks the question of whether you need an external antenna or if you're in a sufficiently dense urban environment, then you could get away with the inbuilt antennas.