I have the JustWatch app, it's very useful, but as far as I know it is only an index of where to find particular videos? Maybe if you have an Android TV (I don't) and install it then it takes you direct to the service. But, personally you pay for each service individually.

Personally, I would alter copyright to create a "most favoured nation" style payment system.

If you provide works to one distributor then any distributor can pay you that price and have access to the work.

Giving copyright holders monopoly control of if works are sold, and a monopoly to the revenue, but not a monopoly over the route from them to consumers.

Exclusivity would be allowed, let's say 3 years (certainly less than 5, minimum of one).

Same across all media. But then I'd also limit copyright terms to 20 years (same as patents).

How does that site work? Do you still pay for every individual subscription?

I just tells you where a movie, series, etc. is available in your country. It shows streaming, buy and rent options, and the prices where applicable. You still need to go to the service yourself to watch it.