They are short of pilots. Currently using wet lease aircraft in Wizz Hungary and Wizz U.K. they have plans for 500 aircraft in the fleet for 2030 I think. Flight cancellations are happening due to lack of crew (inc cabin attendants).
Lauda air have started to advertise with a 5-3 fixed pattern so looks like things are moving again for recruitment. Wizzair will have to rethink the terms and conditions if they want to retain crew going forward.