I feel I am not entitled to any opinion on teh matter as a newbie (and worse: not even an actual user), but in case it helps:
I think the position of the current Help button - below the navigation pane - is misplaced.
To me it indicates that you get general help on configuration matters. Not the context sensitive help that it actually is.
I would put the help "button" on title row like this (very hasty mockup, just for explanation purposes):
- 2021-03-06 16_43_42-Window.png (12.16 KiB) Viewed 1313 times
Then the Jump ... button can take whole width of the navigation pane.
Personally, I don't care for the OK-Cancel-Apply order of the buttons. Just add the regular keyboard shortuts to them
( &Ok; just like the main menu).
EDIT: Skip that last part; bad idea, as those are already in use by the settings themself ...