You are here you must be finding to way to move the search box down to the legacy location (right top of email),the short answer is NO , there is no option to control where the search box will be located. (except you roll back your office to an older version and turn off office updates )
In the earlier of last year , Microsoft already moved search box to top within “coming soon” feature ,when you can un-toggle coming soon to get the search box back .
Then after this change been released formally , it’s not supported to make the search box location configurable. Ever there was a workaround the change registry to move it back but somehow that way doesn’t work anymore.
A suggestion is made on uservoice to Microsoft to allow user to choose the location of search box in outlook, many users voted but unfortunately that suggestion was declined at last, Microsoft was saying the future versions of outlook have compatibility issues with the old one which may leads bugs.
So the conclusion is that’s it ,search box location is not configurable .
The only workaround is to revert your office to an earlier version. One user was saying he/she rolled back to Version 2003 (Build 12624.20466 ) and he/she got the search box back to the legacy location ,the Cons are you need to disable office updates. If you want to do so you can refer How to revert to an earlier version of Office