Windows default app for pdf not taking effect?

Question

EDIT: (Not applicable anymore, question reopened). Why this is not a dupe of the linked question?
The view from the question side: AFAICT (and now I already applied the solution, so I cannot test), in my case the default app change I set never took effect. In the linked question, the title suggests it worked during the current session.
The view from the answer side: The solution there hardly applies here. (Even if it worked, I conceptually think they should not be regarded as duplicates, but this is of minor relevance).
The view from the community side: From the practical standpoint, if tagging as dupe decreases the chances this OP is found, it may be detrimental for others having a problem similar to this one... the search parameters may be (quite?) different from those for the other OP.

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I have both Adobe Acrobat X and Adobe Acrobat Reader DC installed in Win 10, and I want my default app for PDF files (e.g. what opens the file with a double-click in Explorer) to be Adobe Acrobat X only for my user.

• I found no way to make this work the usual way [Settings → Apps → Default Apps], as when I double-click on a PDF, it opens with Acrobat Reader DC [in Spanish]:
• I can Right-click → Open with → Adobe Acrobat and if I select Choose another app instead, what I see is consistent with the screenshot above:
• I tried changing the following registry key and now the default app is Edge; so far, I could not revert this:

   HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pdf\OpenWithList\MRUList
  

Is there any way to fix this, either via the Registry or something else?

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Possibly related:

1. Configuring a default application for protected file types in Windows 10
   a new registry setting in Windows 10 [UserChoice] may be controlling this behavior
2. Unable to change default app for editing scripts in Windows 10
3. Manually Add Program to Open With in Windows 10
4. Set the default pdf viewer app in Windows 10 Registry?
5. How to set Adobe Acrobat Pro or Acrobat Reader as the default .pdf application for Windows 10 users?
6. Setting the Default PDF Viewer
7. Setting the Default PDF Viewer
8. Unable to make Acrobat 9 default with Acrobat Reader DC installed (this entry suggesting the "brute force" approach of changing the executable pointed at in HKEY_CLASSES_ROOT\AcroExch.Document.DC\shell\Read\command)
9. DISM Default Application Association Servicing Command-Line Options
10. Windows 10 – Set PDF Default Application – File Association
11. Fix for “An App Default was Reset” Windows 10 Resets File Associations
12. How to associate a default program during application setup (e.g. pdf files)

Answer 1

The default app per-user is defined via the registry entry HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pdf\UserChoice.

However, setting it directly is impossible because of the protecting Hash entry. If the hash does not agree with Progid, Windows will reset it to the default entry.

To avoid the headache of creating the Hash value, use the SetUserFTA utility. The utility is described and downloaded from the article
SetUserFTA: UserChoice Hash defeated – Set File Type Associations per User or Group on Windows 8/10 and 2012/2016/2019.

Answer 2

The method described by harrymc, with SetUserFTA, works very well. To change the association one has to enter

> SetUserFTA.exe .pdf <ProgID>

The key point, which took me some time to find, is the correct ProgID for Adobe Acrobat. The way I found it is searching the registry for acrobat.exe (launch regedit.exe, and then <Ctrl>+f -> acrobat.exe, with all 3 checkboxes ticked).
I found key HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.eps\UserChoice contains values (as Name/Data) Hash/<hash> and ProgId/Applications\Acrobat.exe

So I executed

> SetUserFTA.exe .pdf Applications\Acrobat.exe

and voilà, Acrobat was the default application. I checked this worked consistently by alternately executing the above and

> SetUserFTA.exe .pdf AcroExch.Document

which alternated between Acrobat and Reader as default applications.

Note that data for the value Hash changed after each execution of commands above, even for the same data for value ProgId. This is the "protection" role of the Hash, and the reason one needs to use SetUserFTA.exe or an alternative method, but not changing directly the data for value ProgId.