decentralization has nothing to do with how frequently you write blocks or how large they are allowed to be (perhaps an argument might be made for security but I don't see how [please elaborate]). If anything I'd say the high cost of entry into mining btc makes it more likely to be centralized. That's why you see massive hash rate drops when problems emerge in specific geographical locations. https://decrypt.co/117916/bitcoin-hash-rate-suffers-near-40-drop-amid-u-s-deadly-winter-storm

Monero is very likely more decentralized. A lot of us run a full node on our own, and p2pool makes pool mining accessible without compromising on decentralization. A lot of bitcoin is mined in datacenters, and many people still haven't learned that they should be holding their own wallet keys so a lot of bitcoin actually lives on the central exchanges. The [US] government even wants to make holding your own keys equal to being a bank to try and keep it that way.