I am already working full time remotely in the middle of the woods where there is "no cell service" getting 6 mbps up and down on an unlimited plan with a super high gain antenna aimed perfectly at the tower through several miles of trees. Once 5G modems come down in price my throughput will only increase. Coverage is already amazing on the under 700 MHz LTE bands even with carriers that traditionally have had a reputation for terrible coverage - even when the tower cells are aimed in the wrong direction! (They are aimed at the town and highway nearby, away from me.) High gain antennas are the most important component of my stack.
11 dBi Yagi Antenna for TV White Space (470-862 MHz) is my choice for extreme penetration. It's several feet long.
I don't trust the specs of the parabolic antennas on the market. They are supposed to be better but I have heard from multiple reviewers on multiple products that their specs are wrong and they simply don't deliver high gain at low frequencies when advertised to be tuned for 4G LTE. I think it is because to cover 4G LTE bands fully you need to support a ridiculously wide range of frequencies from 600 to 2200 MHz.
My low frequency LTE yagi is awesome for difficult wooded areas. It can shoot through at least 3 miles of trees.
I think your Proxicast peaks at 11 dB gain and you need to check which frequencies that's valid for. With such a large frequency range spec'd on that you can't be sure you have high gain on all frequencies. It can drop off drastically on important bands.
That's why I have a dedicated yagi for low frequencies and a similar antenna to what you have for ~2 GHz bands.
I found through experience the best proxy for correct antenna aim is an upload speed test. And the best way to determine aim is by using cellmapper.net and calculating a compass bearing from your location, then using a compass (app) to aim your antenna. Not the more high tech metrics reported by your modem like RSSI and link quality. They can be very misleading in general and especially when the link is idle.
