Merlin has a lot of free time now that he is at Chaldea. You would think he would use this time to be social and see his old comrades. He does not.
Instead Merlin decides to get back into some old hobbies. (or maybe learn some new ones)
He starts by taking over the gardens at Chaldea. They have never flushed like they do now with Merlin taking care of them. The chefs are also appreciative of all of the fresh vegetables and fruits that they now have access to.
Merlin practices his violin skills and gets them back to snuff. He also learns guitar because he know how to use one stringed instrument, why not another right?
The knights of Camelot and other servants start to suspect that Merlin is avoiding them.
Merlin is kinda avoiding them, but he also gets really invested into writing music and playing it, and working on his garden.
He also plays games and streams too. Merlin uses some type of magic so that people in the past who aren't dead can see his streams and videos too.
When merlin is really bored he will sketch people, plants, and animals too.
Merlin's instruments both have carved flowers on them. It was a nice project for him and he really liked how it ended up.
Merlins favorite song on violin is Fairytale by Alexander Rybak. Maybe he makes a version that uses they instead of she so he can use it as a song for the knights.
His favorite guitar song's are Overwhelmed by Royal and the Serpents, and Sorry by Halsey. They help explain his own feelings for life the knights.
Merlin also learns how to play the flute when he needs a break from strung instruments.
Maybe Merlin thinks that the knights of the round hate him, but they slowly start to win him over?
Mordred begs for guitar lessons so that she can impress her friends with it. (also so she can spend time with her brother/uncle)
Listening to violen helps Lancelot calm his nerves and temper the rage that he feels at times.
Artoria will sit next to Merlin as he practices music (usually his flute, but any instrument works for her) and falls asleep to it. She usually wakes up to either his cloak laying on her, or Merlin himself sleeping with his head on her head and her head on his shoulder. Artoria always enjoys those naps the best. (They are best friends you honor)
Bedivere loves to help in the garden and is always asking Merlin to make him some new flowers to see.
Gawain and Tristan always seem to find Merlin when he is drawing and always ask to join him. They start out pretty bad at drawing, but over time and with merlins help the two start to become better artists.
Maybe Merlin joins a band with other servants? hmmm.
So by starting new hobbies Merlin get his family back, and some new helpful coping mechanisms.