what your risk appetite is, and how much money you can afford to lose
I can afford to lose not more than 25%
There's your answer. I'd say put 10% in if it's a good project and less if it's higher risk.
A good project that fills a niche shouldn't matter how much you put in first (eg if you do 10-100x on it, then you've doubled up at least just from the 10x.
You're also less likely to sell at a loss if you don't care about how much you've put down.
If you want to rate your portfolio, call the mutual funds an asset type 6, bitcoin and eth of type 7 and new coins/low caps of 8 and cash derivatives of 1.
What proportion were 1, 6, 7, 8. What proportion are you happy with (eg I normally treat crypto on its own but did you lump them all together to get 25%)?