I have the same dilemma. Rather my AR750S-Ext is wonderful but my phone slowly loses charge through the day. I have been using it for wfh during covid, with the good 4g (sometimes 5g) signal I get, and this avoids me fighting for bandwidth with the home broadband.

(off topic but I have it set up for loadbancing and fail over, so if the phone goes or I unplug it, the router switches over to the home brodband)

I was considering the Beryl, as USB 3 has a slightly higher spec, but from what you say that won’t fix the problem.

I have also tried using various powered USB hubs/dongles on the phone but it fails to recognise the tether.

I suppose if you must have 24/7 then separate power for the phone and router and use wifi tethering (though this did mess up using wifi access from clients for me).

I just found I have a USB 3 Data and Power Y splitter cable and will see if that will work. The phone does tether, just waiting to see if it charges more than it drains.
https://m.media-amazon.com/images/I/61PS7SAXiFL.AC_SL1000.jpg