Can I Pause and Resume a Long Run?
Yes, and stopping partway is safe. Photos already done stay done.
A long run should not hold your computer hostage. You can stop it, and the photos already processed keep their new dates. Nothing is left half-written.
Starting again picks up where you left off, because the work already done is recognised rather than repeated. Running twice over the same folder does no harm.
Takeout JSON Metadata Fixer shows exactly how far it has come and what remains, and the counts at the end tell you what it did and what it could not. It runs on your own computer and is free for your first 500 photos.