Yes I am also facing similar issue ,as you are asking my phone (Samsung A15) also considerly have low signal bars i.e. single bar or two signal bars when other brand phones Infinix or Oppo or Tecno have three or 4 signal bars but that kinda doesn't effect the strength even with one signal bar my phone doesn't switch back to 2G for calls or has better and similar internet speed to the other phone's.
The solution I would consider for that is to wait a moment when your phone has one signal bar or use the Aeroplan mode once. Or move slightly to the upper or outter area of the house,this will significantly boast the both signal bars and speed strength both.
