Shitty LTE signal at home

So i just moved to my new house and while I have amazing Gig up and down internet my LTE signal sucks. And getting an MCell would be great.

However my alarm system uses LTE and I was informed if i got an MCell it will probably interfere with the alarm. I’m pretty sure it’s cause the alarm uses 3g connection or a specific band.

Anyone have any ideas? I thin if I got an MCell it wouldn’t be thay big of a deal but I don’t really want to risk it. The alarm does use a POE signal to the internet as a backup but the installer seemed pretty adamant that it would fuck up the alarm.

Also would like to add, now that i think about it the LTE signal isn't that big a deal but I think there's a difference between basic call and text right?

I can text ok but calling is garbage and barely works unless I'm outside.

trying looking up custom modem firmware for your phone, different ones will locate towers better or worse, also double-check your APN settings on your phone. If all else fails, try switching to a better carrier

I had the same ideas but it's not just GSM that sucks it's CDMA. I live in a pretty urban area but it's just in a valley with trees everywhere.