Um, except the belchhhhh 🤮 lol

side kick / apprentices / hangers on tied to the main pcs to fill skill gaps ... my apprentice is controlled by your player, so can even split the party. Needs fairly experienced players though.

Small groups may do better with shorter sessions, because they will potentially chew through content way faster than a big party. As the GM, you're going to have a lot less of the downtime you'd normally get while a big party discusses plans.

Fill the party out with NPCs with their own storylines. Make the NPCs interesting characters that the players can interact with multiple times a session. Then, allow the players to control each NPC in combat. This will cause them to grow more attached to the NPCs and cut down on them sitting around while you do everything in combat. If you don't use follower NPCs, make sure enemies never outnumber your players in combat. It becomes much harder for smaller parties to dig themselves out of holes when they have fewer actions. Finally, shift your mindset. The smaller a group gets, the more the PCs become "the main characters." Usually we're telling the story of the adventuring group. Now, with only 2 PCs, we're telling the story of these 2 characters. Since we're only passing the spotlight between 2 characters, the group can focus on each one more deeply. The entire campaign can pivot around those characters without others feeling left out or overshadowed. Make the characters feel important because it is their story now. Your group isn't the Beatles any more. Now they're John Lennon and Paul McCartney . No, that's still probably a bad example. They're Simon and Garfunkel. Everyone is showing up to see them and nobody else. Personally, I love smaller campaigns. It allows us all to focus deeply on the PCs, NPCs, and the world without much distraction. My advice would still be though to get an additional player, if possible, to further insulate against scheduling issues. Otherwise, good luck with your campaign!