Most hobbies that take away from God are undesirable if you want to be a better Christian/do the will of God. Carrying on as normal wasting hours & hours watching TV, playing console/pc games, watching negative movies. Doing negative hobbies, martial arts, boxing, very competitive sports.
Even doing hobbies that are creative such as whittling are not appropriate unless it's going to be used. Learning it is probably ok, if you plan to build different skills.
But all these things take time and money away from godly purposes. For all the time a person wastes per week (7days * 3hours a day = 21 hours a week or just over/under for most people) a godly hobby or activity could be done instead. Thinking about God and not e,g, baseball charts n stats etc. Serves little purpose unless it's a job. I used to spend alot of time away from God but felt it necessary to quit martial arts because of these reasons.
So I was looking for Christian hobbies. Not just hobbies. More than just Bible reading etc. And not too long like visiting old people that's probably not allowed legally in UK anyway (security).
As someone who has had a lifelong interest in arts and crafts, I have to wholeheartedly argue for the case that God Himself blesses us with some of our interests, and very much wants us to pursue them. We honor Him when we use what He gives us.
Now of course, anything can be overdone and take us away from God, but I truly believe He wants us to find balance in our lives and explore the abilities He gave us. If you feel convicted by the martial arts, then by all means, walk away... But I'm sure there are many other things God might lead you to explore.
One of the most fascinating segments in the Bible to me is Exodus 31:1-11--(Here's just an excerpt):
The Lord spoke to Moses: "Look, I have appointed by name Bezalel... I have filled him with God's Spirit, with wisdom, understanding and ability in every craft to design artistic works in gold, silver, and bronze, to cut gemstones for setting, and to carve wood for work in every craft. I have also selected Oholiab... I have placed wisdom within every skilled craftsman in order to make all that I have commanded you."
NOT ONLY did God specifically NAME whom He wanted to make these things for the temple, He also stated that it was He HIMSELF who gave them the knowledge and skill. No doubt, they must have been the best of the best, and in order to get that way, they must have had to have A LOT of practice utilizing their skill.
I highly doubt these guys just opened their eyes suddenly and found themselves bursting with knowledge (like Keanu Reeves in "The Matrix".) Mostly likely, they'd spent their entire lives perfecting their craft, and I often wonder, HOW.
In order to become a master with precious metals and gems, I would guess that you would have to have a rather wealthy client roster (perhaps Christian and non-Christian) to support your work. After all, how many average citizens could afford works in silver, gold, and gemstones? Even if they somehow worked for free (which I would doubt), they would have to work for people who could at least supply the materials.
As with anything, a talent can be used for evil (making a golden calf) or for God's glory (furnishing the temple.)
We might not all be called to decorate a temple, but I know some people who have hobbies in which they make or grow incredible things, and use their talents to help others, even if it's just making someone smile with a garden-fresh bouquet of flowers.
I'm sure you have many God-given talents to explore, Dai.
Please don't let misguided religious restrictions stop you from exploring yours.
Best wishes to you.