Combining two 4g routers into one

Hi, we’ve just expanded our office space to include another floor. And because of that, we now needed to expand our network. It’s an old building, so the connection there is really bad (like 10 Mbit download) so we’re relying on 4g network connection which has been great so far (city centre 200mbit)

Because we’re expanding, we also needed some more bandwith, so i went ahead and got us an extra 4g router to put on the other floor.

I gave it the same ssid and password, so you now just connect to the closest one. This works pretty okay, the only problem is just that sometimes it connects to the wrong network, and your internet becomes really slow. (Or whn you mov between floors)

Is there anyway to combine the 4g routers in a better way? Like a mesh or something?

Any advice is appreciated!