A Good Snowman Is Hard To Build is a very cozy puzzle game. You are in a garden, separated in small areas, with three snowballs on the ground. You can increase the size of one ball two times, by rolling it over snow. You need to get one big ball, one medium one, and a small one. Then you have to push (not pull, you can only push) the medium ball onto the big ball, and then the small one onto those two.
It gets kinda hard relatively fast, but I haven't really tried the ones that didn't get solved immediately. I also guess it's pretty short. According to How Long to Beat, it's between 2 and 4 hours. But it's cute, the music is calming and the whole thing is just a relaxing experience with no time pressure.
I also played a chunk of Cosmic Express, from the same studio. Also a relaxing, very cute, 2d grid-based puzzler. You have to build the rails for a train from a fixed start point to a fixed end point. But there are people you have to pick up (the train has go over a neighbouring tile) and let them out at their house (also go over a neighbouring tile). Depending on the world, you could have two seats instead of one, or passangers who make the seat icky, so guests of a different species (they are all cute aliens) won't get inside. Stuff like that. The same relaxing vibe, but gets pretty challenging.
I got both from one of those itch.io bundles, so no idea how much they cost. But if you want a challenging, relaxing, 2d grid-based puzzle game, these two should fit well.