Even though this feature is unavailable I found a way to not get bogged down too much doing it manually.

Perform a search against Inbox that will return all the same emails your rule would catch.

Select the first one.

This is the worst part. Scroll three screen lengths down at a time. Each time, shift-click the checkbox of one of the search results on screen. Then continue scrolling three screen lengths at a time, shift-selecting each time, all the way to the bottom of the results.

Now move all the selected results to your target folder, or whatever you were going to do with them.

(If you try to scroll all the way to the bottom, the shift-click won't work, at least as of now.)

There is a limit (250 threads) to the number of search results you will be shown, so if you exceed that limit you will have to repeat even this procedure several times until your Inbox is clear. However, do not repeat your search immediately. Do something else for a couple of minutes and then come back and do it. Because the emails will be moved/processed in the background, and until that completes, the same search results will be returned, and you will repeat your work. There is nothing in the UI to tell you that this is happening, but when the work completes, the search results will be different.

While Microsoft could just implement the "run rules against inbox" feature that other online email clients have, this procedure is still way better than moving them one at a time or 8 at a time using the "select all (at the top)" button.