In my opinion, Bitcoin Core 30 could very easily destroy Bitcoin. If Bitcoin turns into a crypto blockchain like Ethereum, where it becomes centralized and only large companies can run full nodes, that would be the end of decentralization.And if that happens, Bitcoin can no longer be good money. If only a small group of people like in Ethereum get to make decisions, then we’re just recreating a central committee, like a central bank in the fiat system.
Core 30 is simply increasing size limit of OP_RETURN, it's not about centralization, rather it's still about doing decentralization without censorship of any transactions kind.
You can run Bitcoin core 30 and choose not to relay transactions with OP_RETURN, you will still be fine instead of running to knots but it's still not bad.
The concern here is, the developers are trying to make alternatives for people that want to send and store an arbitrary data into Bitcoin blockchain, there are so many people spamming different data on Bitcoin UTXOs, they are expected to be spent but the trick is, the UTXO are fake pubkey without private keys. So they remain there forever and if this continues, the UTXOs will keep growing with spam of fake pubkeys.
We can only hope this upcoming upgrade makes people to use OP_RETURN instead of this continues spam but my opinion, this upgrade doesn't change anything.