gateway dropping connection multiple times a day

we have been experiencing an issue with our wifi for a month or so.  when it works, it's great, but it is literally disconnecting the internet randomly, several times per day.  Just last night, it was the worst yet, and dropped several times in 1 hour.  It has gone back to it's normal, dropping the connection just randomly.  Today, It's only dropped the connection about 4 times so far and it's just now 2pm.

We've only managed to contact support once, because generally, the disconnections are very SHORT in duration, so we never get a chance to reset the gateway before it goes back to normal.  sometimes we disconnect all the wires (including power) from both the wall and the gateway, and leave it for a few minutes and plug it back in.  Sometimes we go through the app to reset it, if the app actually works.  

In the last month, there hasn't a time where it's "been good" for a whole day.  we live in an apartment, and have had this gateway for a few months, it was provided by xfinity. we aren't on "storm ready" wifi, just gigibit.

we have one computer connected via ethernet, everything else is wireless.  during the day, several devices are connected to the gateway, but not all active... as opposed to nighttime, where there is about 10 devices connected but only 3 active.  the gateway disconnects whenever, so it isn't related to how few or how many are connected.

any help is appreciated, thank you!