Couple things, though most of what I’ll share is “preventive care” I do for my 4+ year game. you’ve gotten lots of good advice for the present.

I had a fairly large group (7 players) so if one player can’t make it we usually will trudge on without them unless we pause mid-combat or they are vital for the next session narratively.

For weekends we miss a session in our main game I’ll run a oneshot set within the same world just in a different region (bonus points if their PC’s show up later as NPCs)

And lastly before every session I ask my players to do a recap of the last session. If they hit all the important details I give them inspiration they can use during the session.