I recently bought a CAT S42 smartphone to replace a many year old CAT S41 phone that is dying. Figured it was the next model in the line, should work as well with LMP as the S41 did. No joy. I returned the first S42 due to GPS problems, got a replacement and see the same issues. Debugging and problem isolation on this has been a real challenge.
It would be much simpler to just return the S42 and buy some other brand/model that is known to work well with LMP.
My usage is that I ride dirt bikes (motorcycles) in the boondocks. I use LMP for navigation, and for track creation for future rides. I need a solid, reliable GPS. Its got to be rugged, since I crash the bike a lot. I've destroyed 3 or 4 normal smartphones before I got my S41. Speed, style and price are not major drivers for me. It has to work great with Locus Map Pro.
Have a look at Blackview. They have a line of rugged phones, and I've just received my second one, a BV9900 Pro that I'm very satisfied with. It works like a charm with Locus. My previous Blackview survived, among other things, a short quick roll down a 45-degree slope before a tree stopped it. There are videos of the phones being abused quite severely. If you don't mind ordering from AliExpress...
There's a thread discussing the phone here:
https://forums.geocaching.com/GC/index.php?/topic/358448-gps-glonass-beidou-galileo/
PS, it has quad-constellation support! Single band though. Still, a fix with 25-29 satellites is pretty darn good.