When editing a record, clearing a field or linked record is done in a millisecond. I am afraid users might do this by mistake, it happend to me when testing the system several times.
There is no Undo function, and I can understand why. It would mean you’d have to have a method to rollback and commit changed data. If two users can have their fingers on the same record at the same time, you need a complex method to make sure the data stays correct.
There is a way to fix this. Introduce a SAVE and CANCEL button in the (old and new) record experience screens. Just like it is with automations. You can’t leave the screen without saving or cancelling. And if it would have a short cut key like CTRL+Enter, it isn’t slowing down the user.