Guitar Fingering in Musescore 3

Yes, you can define a shortcut to disable automatic placement for selected elements. Do this in Edit - Settings - Shortcuts. Search for "auto" and define a new shortcut for the second entry in the list (or global (first entry))

First, you don't need to uncheck autoplace to get the results you show here, and in fact it works far better if you don't. Try it - nothing prevents you from moving the fingerings onto the staff if they aren't there by default (which they are in most of these cases), and if you don't uncheck autoplace, then MuseScore can at least avoid collisions with other things on the staff.

The reason you are seeing your fingerings not already on the staff by default is that you entered them incorrectly, using the plain Fingering elements meant for piano rather than the guitar-specific elements further into palette. If you had used those, you may not have needed to any manual adjustment at all.

Luckily, it's not too late to fix - just right-click one such fingering (the "1" on the first chord, say, then Select / More / Same subtype. Now hit Ctrl+R to reset your manual adjustments, then use the Inspector to change the text style from Fingering to LH Guitar Fingering. The results may or may not be exactly what you want, but they are certainly a lot closer than what you started with, so much less manual adjustment would be required.

As mentioned, disabling autopalce is definitely not needed, and is in fact counterproductive, when adjusting elements like this. But for the record, you can use the shortcut "=" to disable autoplace for an element, or use Ctrl+drag to disable while moving, should the need actually arise. The only place I can see that happening in this score are the places where you chose to move fingering to the righthand side of the note that normally would be on the left. My guess is the only *reason& you did this is because with autoplace disabled, there was no additional space allocated to avoid collisions with the barline, and had you used LH fingering and left autoplace enabled, then that space would have been there automatically.

You can even define a shortcut to completely disable autoplace (go to Edit / Preferences / Shortcuts, search for "auto"), but this is an extremely bad idea overall, as you will quickyl realize just how much work autoplace is doing for you to avoid collisions that you will now have to do manually. And then redo the next time you (or someone else) make any change to the layout that invalidates your manual adjustments (like changes staff or paper size, etc).