There has never been a level playing field. As you have said, most european carriers require crew to be fluent in their countries language, I cannot see that changing.
You only need to look at the fun and games with the Astrazenneca Vaccine to see how Europe feel about the UK, the lack of take up is insane.
As to pilots, well there are plenty of them in their own countries. EASA has already said the UK issused Licences are 3rd Country, that wont change.
Balpa are very good at making noise, not seen much change though.
UK Cargo companies, some are already moving their aricraft to the European Registry, removing the need for UK Crew.
Sadly this is just the start. It is a massive mess, as I said in an eailer post, there are 10,000 pilots unemployed over Europe, it will be a while before any cadets are hired, I would hang on a year or two to let the dust settle