This is your local problem. Nothing haven't happened with the search engine and copy-paste function, it works. Maybe you could give us a little more information about your current system and its configuration.
It's the same in 20Hx It does not work over the magnifier glass icon, and sometimes over the text Search local disk... You just have to first left-click in the search box, then do the right-click in the empty space while the cursor looks like ][ Different DPI might make this harder. Definitely an ugly usability regression.
Please try, i can left click in the explorer searchbox wherever i want, no rightclick context menu either, ctrl-v works.
In my work, I constantly have to look for different documents on different removable drives . That's why CTRL-V is annoying.
I can look anywhere, but at the moment I have 4 completely different computers. Three have a clean installation and one has an update using KB4517245. Everything is 1909 OS Build 18363.418 and copy-paste works just like it used to on all computers.
I would not put an insider preview (20H1) install on a work pc, only to have the rightclick context menu paste option available, if it is a bug, it will be fixed by CU (on 18363.448 it's the same).
I'm not seeing this issue on my end. I can right click in the search box and paste. The new style search doesn't appear to be active here. Results appear as I type into the box as well. 18363.448
I know, it's the same in 18999, does not work directly, only after a left click like you've shown. I guess this bug is here to stay?
damn that's even worse, kinda what microsoft has gotten us used to, all these windows 10 RTMs the insider program would be so freaking effective under a competent leadership.. but nope
Since that new search box is UWP-based, maybe it need those https://forums.mydigitallife.net/threads/solved-cant-copy-paste-in-modern-apps-from-store.80188/