> From a user perspective, blockchains are less secure as there is no authority you can approach for chargebacks

This actually proves the point that security is relative. There are instances when I would feel more secure when an outside party can refund my money, say when the seller never ships the product I ordered. There are also times when I would feel less secure with chargebacks, like when I sell something on eBay and the buyer files a complaint with PayPal after taking delivery of exactly what they ordered.

Security wasn't an original goal of bitcoin. Privacy, anonymity, and immutability were, though the first to were lost a decade ago and immutibly is pretty well solved but also the primary cause for so much wasted resource consumption.

> There are instances when I would feel more secure

Your comparative examples make no sense - you like refunds as a customer and hate refunds as a vendor.

Surprise, surprise…? I mean this is already the case in web2/fiat.

It sounds like you did understand my two examples, not sure how they could have made no sense. The two scenarios point to competing ideas of what "secure" would mean, and my point was that security can't be a goal because its relative

can you explain how web3 solves your issue?

Oh it doesn't, I haven't found any value in web3 yet. I may just be missing something, but I still don't get what problem web3 can solve that isn't solved easier with web1 or web2 technologies.

> From a cryptographic perspective, centralized and decentralised services are equally secure

That’s just not true