BIRDIE I live in a rural area and don't use my phone much while home. Reception is negligible even with assist.
I live in a fairly urban area with solid LTE coverage. But my home and around 20 others are in a bit of a dip which is an LTE hole. I have a Samsung LTE extender that makes regular phone calls work.
And so do a bunch of my neighbors! Carriers know exactly where each LTE extender is, so my carrier must know they have a coverage hole in my neighborhood. But I guess it's fine for them because we are all paying for the cellular infrastructure and also for the backhaul.
If you have an extender and still have trouble, maybe see if a nearby ham radio operator could help it work a bit better.