I'm writing to ask about the regulation about investing and stock trading in the UK, specifically with regards to my Skilled Worker Visa.

I know that self-employment is not permitted for me, but I'm wondering if it's okay to invest in stocks, bonds, FX, crypto, or ETFs, and do some day trading on stocks futures or CFDs?
From what I've read, any profits from these activities are usually considered capital gains and not self-employment income. Can you then confirm that this is ok and that I won't breach my visa conditions?
If I can do these things, could you also let me know how to report any earnings to HMRC? And is there a limit to how much I can make from all this (as a Skilled Worker visa holder)?
Thanks for your help, I really appreciate it!
Best regards,
Alphonse