Being a flight instructor in the EU is ok if you just want to stay in the air and make a bit of cash while waiting for an airline interview. But honestly, those FI hours don’t really count for much and won’t give you big advantage when it’s time to move on to airlines.
I’ve got a buddy who went all-in on the FI route—he’s got like 5000 hours instructing now, but no flat, no car, no family. WizzAir recently turned him down, and now he’s actually thinking about paying for his own type rating. It’s a risky move as airlines aren’t exactly lining up to hire 45-year-old instructors.