This preprint paper found that are BTC and BCH mining are equally de/centralized. Statistically, there are 8-9 equally powerful miners on both BTC and BCH (BSV has 4). Long, Sishan, Soumya Basu, and Emin Gün Sirer. "Measuring miner decentralization in proof-of-work blockchains."arXiv preprint arXiv:2203.16058 (2022).
The authors of this paper found that the number of unique nodes that created a block per year peaked at almost 70,000 in 2010 and has since decreased to submitted by
