I was told by an FA when I was flying to LIS, which also requires masks, that the FA policy now is that they make an announcement and if you choose not to comply, they leave you alone. Obviously we unfortunately have our fair share of militant FAs so act at your own peril, but as long as you're on board, their only job now is to inform you of the policy but they can't ban you or whatever anymore. I'd verify this with the crew on your flight to make sure they're cool, but most don't really care as long as you're wearing it getting off the plane going into the terminal.