I don't know if I'd go all-in on replacing a gas grill with a pellet smoker. Why not both? Those two each have different purposes for what they're best at.
I have a built-in gas grill and a pellet (mine is Traeger) and I find that I mostly use the smoker for those long low and slow cooks - brisket, pork butt, ribs, etc., which tend to happen less frequently for me these days with kids stuff every weekend. But for fast grilling - burgers, chops, chickens, fish filets, etc. or searing rare/ med rare steaks, the gas grill that gets really really hot and really quickly remains the more daily go-to. Obviously, you CAN get your pellet smoker hot enough for burgers, chicken thighs, etc. and it will add smoke flavor and make your back yard smell better when grilling, but it takes longer and requires buying a lot of pellets vs the easy always flowing permanent gas connection.