You can easily nudge, i.e. add or remove frames with the [F5] or [Shift+F5] shortcut. I have changed that to [Z] and [Shift+Z] which is even easier to press. You can press and hold, or press multiple times. Without a selection this would work on the whole timeline. With a selection on the selected spans. If you select, for example, a block of 5 frames, 5 frames will be added or removed, and so on... The timeline navigation may be a little different, but is fully-functional, so maybe if you do a screen recording in which you show the specific problems you face, users here would be able to guide you on the optimal way of dealing with them.
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