Can I ignore specific folder from being scanned?

[DogmaDragon]

Yes. You can set it to be excluded using regular expression (regex).

1. Go to Settings > Library > Exclusions.
2. Click on Excluded Video Patterns or Excluded Image/Gallery Patterns depending on type of content you want to exclude.
3. Click Edit.
4. Enter valid regex and click Confirm.

Note
There is a useful regex101 site that can help you experiment and test with regex.

See Stash in-app documentation for some examples:

Configuration - Stash-Docs