@portsharbourflyer
What you say is partly right, but certainly not the whole story.
You imply that all UK based aircraft post-2022 need to be on the UK register. That's simply wrong. Ryanair and others can base EI/SP/9H etc. planes in the UK and fly them UK-EU without restriction. Obviously UK license holders won't be eligible for these jobs - though the EASA license holders will require the right to work in the UK.
We simply don't know how many Ryanair aircraft based in the UK will be G-reg. They obviously would rather it be zero and the likelihood is that it won't be that many.
easyjet will inevitably need to move more aircraft onto EASA country registers, but there's no indication of UK based aircraft doing that that I have seen so far. Wizz UK (don't spell it Whizz on any job application!) seems to have a lot on the UK register at the moment which is good. However, plans might change.
TUI's plans seem to indicate further integration of their units. I think the likelihood of lower-cost Spain/ Greece based aircraft is getting higher by the day and, as they will operate to multiple countries, they'll need to be on an EASA register.
For all operators, we don't really know how flexible wet and damp leases will be and how strict the CAA will be with enforcement and we won't know until at least 2023 (Don't forget, what's planned/ written down/ said doesn't always match with reality).
The real truth is none of us know what will happen post-2022 and post-Covid restrictions (when they hopefully come!). Nothing can be totally ruled out. Not even the UK rejoining EASA (but that is entirely down to politics so not really for this part of the forum).