From what I’ve understood after studying crypto stake pools is that:
i) If a person has sound technical skills, then this can be done without any intermediary i.e. there’s no borrower involved. The software algorithm decides the new/additional coins without any human intervention.
ii) Riba is in transactions where there is a loan involved i.e. borrower and a lender, with lender demanding an additional amount over and above the principal amount, thus resulting in oppression and exploitation. In crypto-staking, the lender is not demanding the return, it is infact the software which determines it, which reduces the element of oppression and exploitation. Infact, the additional coins given to the investor are not resulting in oppression and exploitation of any other party to begin with.
Therefore, I personally do not find an element of riba in such transactions.
P.S. I am not an expert in this matter, neither am I a scholar.