how to recover accidently deleted back ups from an old time machine disk (no longer in use as time machine on my current macbook)

How to recover accidentally deleted back up folders from an old time machine disk (no longer in use as time machine) back to that old time machine disk?

To make space on an old time machine disk that I only use to access old files (via the finder), I deleted old back up folders, keeping on the latest one, by dragging them manually to the trash. When I now click on "info" the time machine disk still seems to hold all the files (a total of near 1,5 TB). but when i click on the finder > backup > sophiekrier's computer> there is nothing there anymore....

Is there any way I can put back 1 or 2 old back up folders on the time machine so it gives me again access to the files? do i need to set it up as time machine again for this? (this backup is from a former mac book. I now have a new macbook with a new timemachine).

thank you for helping out.