When I moved into my new house but the internet fiber was not yet activated I also used a Pi with a Huawei 3g dongle as gateway for my home. Most expensive internet I had to use for 3 weeks.
Didn't have any reconnects though but I had a script running checking the connection and if it failed it would re dial
Didn't have any reconnects though but I had a script running checking the connection and if it failed it would re dial