I’ve got heat pumps and they work fine as a primary. They keep it at 70 for us year round with minimal fuss. I didn’t pay an extra huge premium for any fancy model either as far as I know. Newer ones work well into single digits very efficiently and still work into lower temps than that, but not as efficiently or quickly. Having a backup source for the coldest nights is a good idea but not a necessity. Heat pumps and air sealing/insulation work would be my solution for the OP.

It was 13 degrees when I woke a couple mornings ago. Heat pumps were still blowing warm air. (Efficiency probably goes down a bit, which is why I still have the oil boiler ready to go.)

We live in an old farmhouse and have done a lit of airsealing and insulating this year. We have relied on our heat pumps all winter, and it's been much more comfortable than when we relied on pellets and propane. Temps stay mid- to lower- 60s in the areas furthest from the air handlers, and we've got the thermostat at 67.

Yesterday was the first time we put on the pellet stove and that's cuz we were sitting around hungover and wanted the ambiance.

We haven't turned on the oil yet this heating season.

Don’t know what heat pumps you got, but ours are more efficient than the oil baseboard system until about -10 (theoretically, we haven’t had much under -5 in the last few years). The efficiency also only really drops at -5. Daikin is our brand, they’re awesome and the reduced AC costs in the summer are massive as well.

I remember a time where our house didn’t have AC in the summer as kids because we didn’t need it!