Like others have said, if your skin is fine and happy keep things simple. Don’t worry about getting a routine going, if doing nothing worked for my skin I would totally do that!
That said, if you liked the sheet mask, it was probably having a little more hydration that made things feel good. In that case you could add a simple moisturiser, maybe for night time so you can wake up extra moist, which does feel nice.
I put on a lot of moisturiser, because I am the desert without it. I use AHAs etc, but when self-care is a struggle for me I will just put some German Nivea cream or Illiyoon Ceramide Cream on and call it a day.
The process of it can totally be self care. I used to love the Pumpkin Sleeping Pack too. A sleeping pack/mask can be great, particularly one that feels substantial on. Products with great sensorial aspects can be lovely to use.