home internet weak signal

for the last 3 weeks I'll have to move router inch at a time an it jumps from 1 bar no signal to 3 bars and no signal every 5 min I've reset unplugged everything whats worse is we live in a rural area so it's either t-mobile or back to half a megabit a min with century link and through phone line. We've been fine with between it showing 75 megabites an up but the signal strength to my ps4 is like 2 to 500k but on app it always say 75/75 do I need to just upgrade to the square 5g router? Now our router only shows the 5ghz signal usually its 2.4ghz as main and 5ghz