I don't know what's the name of dongle though, it was similar to those sd card to usb thing ykwim, I'd appreciate it if someone could help find this too if possible
but also yeah your point is also fascinating as well, y'know another benefit of doing this is that atleast in my area, 5g (500-700mbps) is really cheap (10-15$) with unlimited bandwidth per month and on the ethernet side of things I get 10x less bandwidth (40-80mbps) so much so that me and my brother genuinely thought of this idea
except that we thought that instead of buying a router like this, we use an old phone device and insert sim in it and access router through that way.