I do suspect this is just another EMDrive. Interacting with the vacuum to shift energy around is well-known (again, see Hawking radiation [1]), but holding on to it overall for long enough to violate the uncertainty principle (the one for the E-t commutator [2]) doesn't work. And I don't think you can hold it just long enough to reverse entropy... though that doesn't sound prima facie impossible. Making a measurement incorrectly, though... I do that every day I'm in the lab.
Addition: Also, the MDPI journals are kinda-sorta just one step up from trash-tier, at least in my mind, so I don't pay much attention to work that can only manage to get in to one of them.
[0] https://en.wikipedia.org/wiki/Pioneer_anomaly
[1] https://en.wikipedia.org/wiki/Hawking_radiation
[2] https://en.wikipedia.org/wiki/Uncertainty_principle ...at least I think it's in there somewhere. Otherwise grab Griffiths!