What kind of financial institution has a special deal with Netflix to prevent blocking their charges? Did Netflix threaten to block Revolut or something?

If a merchant gets a lot of charge backs from a specific card issuer or acquirer, they can block them specifically. A company at Netlifx's size could be doing this, but I've heard specific instances of it happening with grocery stores, gas stations and convenience stores.

It's very common for neobanks to have a high rates of fraud, but also lower negotiating leverage with merchants because they're not chase, Wells, etc.

So a specific arrangement with a specific merchant seems within the realm of normal to me.

My card issuer just gives me a credit when I want to chargeback. They're like, oh you don't want to deal with a real chargeback, just have your money back for free. I would've pressed it since I kinda wanted the company to regret ripping me off, but I already got my money back so it wasn't worth the extra effort.

That's how chargebacks often work. Then they ask the merchant for evidence the charge was legitimate. If convinced, they will retract that initial quick refund.

Real chargebacks claw the money back from the merchant. They don't just provide a credit.

the great thing about Revolut is that a) you can create multiple free virtual cards (with numbers different than the physical card) b) you can attach spending limits on each c) you never use the physical card details online d) you can cancel a card as soon as you notice a suspicious transaction which you have not done yourself - for this you can even use the virtual disposable card number. If a subscription was authorised previously on a card, you should have the track record from the transaction history, too.