A small feature that would go a long way is, enabling users to set priority orders when managing streaming services. Many users have a preference for services when content is available from two resources, and enabling them to set that would be a huge help.
What are you trying to achieve?
Given that Plex doesn’t actually play the videos from streaming services.
Just guessing…
If you click on a movie which is available from more than one service, then automatically use the streaming service which has the upmost position in the priority list of streaming service that he mentioned.
You cannot use streaming services from within Plex.
I am not using streaming stuff from within Plex.
What happens if you click on a movie which is available on multiple streaming services?
Is Plex opening a new browser for a selected service? Is it just cover viewing? 
You can see a list below where it is available. Provided that you have selected the streaming services that you are actually using in your user account, it should preferably show those and hide all the others under a “More…” button.
Okay, understood.
So, it’s basically an info about streaming services for a movie or show?
Maybe the person starting the thread wants you to open a streamer app or browser window on supported devices… accoring to the afore-mentioned priority list. 
Maybe the info list should be sorted according to the user’s taste?
The fact that Plex doesn’t technically play streaming content within the app is another problem, but this one is adjacent. I’m trying to suggest a feature within Plex that plays movie or television content from the users’ preferred streaming services if it’s available on two platforms.
For example, some services offer Dolby Atmos and others don’t. My preference is to play the highest quality content. If The Matrix is available from Paramount Plus and Netflix, which version will play when I instruct Plex to start the movie?
Currently, users can select which services to which they have access, but there isn’t any priority order for accessing the content.
That’s it!
I’m not really clear
You search for a movie select it and land on the universal details page. It available on a bunch of services, 3 of which you have set and those three are shown on the universal details page. Clicking on any of them will open the streaming service app that you pick if you decide to watch movie
When does this happen? when you click on the the movie in search? It skips the detail page and just opens it up on the other service? What if you are just browsing and not sure you want to watch it and only want to view the summary?
Plex cannot start any movie from any external streaming service. I’m not sure what you mean by this.
You have to open an addition set of menus to pick from the options based on pricing. If you have the service, the “Play” button should be available immediately, just as it is with content available directly from Plex.
When content is available directly from Plex, a “Play” button is included in the top menu, enabling you to bypass selecting which provider will play the content. What I’m suggesting is using the same for times when you have already identified to Plex you have that service. When more than one service has the content, and you have subscribed to both, the play button should play the content from the provider with a higher priority on the list.
but Plex cannot “play” any content from other providers. So i don’t understand what you mean when you say that.
I think you’re taking this too literally. I’m not sure what you mean by “doesn’t play content,” but when you select a service from the list, it initiates that application in some way. Even if the play button on these screens is a function that skips to whatever command starts the apps is a move forward.
He means he would like a priority order for the streaming apps that titles are available on, so if they are not in his Plex Media Server libraries he can just hit play if it is available on the streaming services he is paying for.
For example he has Netflix highest in a priority order because he pays for it. Despite the title not being in the PMS libraries, the play button is still available because it is on Netflix, clicking play will then open the Netflix app, and because he set Netflix highest in his priority streaming order it is that Netflix app which opens and not Paramount+ if even he has Paramount+ and Paramount+ has the title too, because Paramount+ is below Netflix in his priority order.
If Netflix doesn’t have the title and Paramount+ does, then it will be Paramount+ that opens so he can watch that title.
