Despite some Journal entries (mostly in Sukhothai) being unavailable or not counting, the achievement for collecting them all can still be unlocked by taking pictures of hints in previously completed puzzles. Doing so updates the total number of Journal entries which tricks the achievement into unlocking since the number is the only requirement.

If you have not already taken pictures of all hints, do not do it before the unobtainable Journal entry (or entries) are the only one(s) remaining, otherwise this workaround will no longer be an option as explained above. Some puzzles might not offer prompts to view or take pictures of hints when revisited and it is even possible for the game to crash as soon as the camera angle is right. In that case, visit a different puzzle in the meantime and try returning later.

Save files are encrypted and tied to unique Steam IDs, so finding and loading someone else's save files with 100% completion is not possible.

Official information available here:
https://help.bethesda.net/#en/answer/68277

1) Tower of Nicholas V - head down the broken spiral stairs to find the Sacred Wounds Mural where the 5 switches used to be.

2) The Fountain of Confession - check puzzles on the sides of the construction surrounding the spiral stairs and the statue right in front of the stairs.

3) Fountain Underground - after reaching the main chamber which splits into 2 paths, return to the Gold Trial Puzzle upstairs and reach the plaque in front of the pillars.

This is the location that used to cause my game to crash to desktop as soon as the camera angle is right despite:

-verifying integrity of game files
-rebooting the game in Safe Mode
-using the Save Rollback function in Game Slots
-backing up, then manually deleting all local save and configuration files, disabling Steam Cloud, opening the game and starting a New Game, reaching the first checkpoint, closing the game, enabling Steam Cloud and overriding all local files with the backed up ones

The game would still instantly crash without an error every single time, so I gave up and moved on. Eventually, I returned to this area to take a screenshot for this guide and tried to take a picture of the plaque one last time since I was already taking the time to revisit all of these puzzles and it actually worked somehow, so the achievement finally unlocked as I'm typing this. Whether the list of things I tried had anything to do with it or not is unclear.

4) Great Sphinx - head underground through the wide entrance on the side of the Great Sphinx (not the one directly behind it) and reach the mirror puzzle in the throne room where the Gold Mask used to be.

5) Great Sphinx - the Statue of Light just below the throne room.

This is the only other location where I was missing a hint. I actually revisited the throne room a couple of days ago, but completely forgot about this puzzle...

6) Ancient Caves - find the entrance near one of the pyramids between the Khafre Excavation Khentkawes Excavation, then reach the Three Eyed Gate.

7) Captain's Lounge - check the cipher puzzle in the room where you end up by default after traveling back to the Himalayas.

8) Hidden Pyramid - in the narrow passage on the way to the Hidden Pyramid area, look to the left for the first cog puzzle which was needed to open the gate.

Here, it appears as if a hint is missing for me, except it isn't. Each time I take a picture (which I can do endlessly), a Journal update notification still appears in the top-left corner. This is just a cosmetic issue with no real effect on anything.

9) Hidden Pyramid - the second cog puzzle can be found just across the river. Unrelated, but in case you cannot find the last 3 out of 10 cogs, they most likely remained in one of these puzzles.

10) Wat Mahathat - go back inside the temple and reach the Game Room, not to be confused with the smaller version inside the Hidden Pyramid which is no longer accessible.

11) Wat Si Sawai - in the underground temple, reach the main chamber, take a right and descend to Khmer Pipeworks.

https://steamproxy.com/stats/2677660/achievements