This is actually the first time I have seen someone put the 50/30/20 strategic budget/planning into play, and you are actually doing something good with your 20% by investing it in crypto, but if I were in your shoes, I couldn't invest more than 15% and leave 5% as fiat savings in case anything comes up that is not included in the 50/30 budget; I can easily put my hand in the 5% reserve fiat and save myself the stress of selling part of my acquired crypto unripe.
Sounds good too!
Everybody does what suits him best, and after all - the budget would still differ due to the real numbers, but we wouldn't look at them - risks should be managed appropriately, that is all to it, no matter how much there are funds.