If it's what I think you're asking, you would go to the instance that you want to open the post on and do a search for that title, with the search type as "posts". The instance you're on has to look it up because everything isn't automatically on another instance. Also, both instances have to be federated to each other. I personally, haven't had good luck by doing the generic address way of posting.

Most apps handle it internally, but if you're on the web browser you can use the Instance Assistant extension to do it for you. It adds a little "open post in home instance" button

The short answer is that you have to ask blahaj.zone to resolve it. lemmy.ml has it as post id 11470168, but it'll be different for other instances - whatever the next number was in their database when the post was announced.

You get different answers depending on whether you're logged in or not though.
From endlesstalk.org, I can search for that post in the web-ui: Communities -> paste the post url into Search -> Change the Type from 'communities' to 'posts'
Alternatively, using the API, I can resolve it with
curl --header 'accept: application/json' --header 'authorization: Bearer MY_LOGIN_TOKEN' https://endlesstalk.org/api/v3/resolve_object?q=https://lemmy.ml/post/11470168

I'm not logged into blahaj.zone though, so it won't resolve it. The web-ui only gives me this post as one that mentions the thing I'm searching for, and the API returns 'not found'

Drop the permaurl/fedilink into your own instance's search box. Note that you have to be logged in when searching for remote content otherwise it'll silently find nothing, probably to avoid abuse of server resources.

Related minor issue https://github.com/LemmyNet/lemmy-ui/issues/2160

And pull request with the fix https://github.com/LemmyNet/lemmy-ui/pull/2344 (give a thumbs up or comment if you want to see this fix accepted)

Basically if the colorful fedilink icon is not there then you can just copy the URL from your address bar cause you're already on the local post. Posts are local to the instance of the poster, not the instance of the community.

Here's a couple of feature requests filed for improving the core issue: (give them thumbs ups)

https://github.com/LemmyNet/lemmy-ui/issues/2318

https://github.com/LemmyNet/lemmy/issues/2987

You can also use https://lemmyverse.link - you can either put the URL on the homepage, or it's not even hard to create it manually - your post (https://lemmy.ml/post/11470168) has the URL https://lemmyverse.link/lemmy.ml/post/11470168 - that way everyone can choose their own instance and be redirected to the post on their own instance.