Yes I've played several 2 person ttrpg campaigns over the years and there is a very specific buy-in from GM and PC to really feel like we're not just doing some weird back and forth. I've done it with very mechanical rules lawyer types and it did not go well. I've enjoyed it when it's in the 'hey, it's like where playing couch coop Super Mario World.'
My current in person Deadlands game just ballooned to 5 and its been going well so far. My concern becomes that it's harder for the characters to have meaningful interactions, and then there are more scenes to bounce around, and etc. and etc.
But everyone has been really supportive of each other and sharing focus and all that good stuff so it's been great so far. It also helps that we use zero tactical play at all 😅--at least not any that make physical sense; fictional sense heck yeah!