My offer from 2022 still stands, you vanished back then and did the same again in 2023 without posting it from what I remember:
As we are both in the UK you can send it to an InPost locker so neither of us have to reveal our addresses if you feel better doing it that way.
Or if you purchase something like this: Cart Flasher for GameBoy from J.Rodrigo on Tindie I can help you dump the save over remote assistance. I also have a tutorial on how to do so: GameBoy / GameBoy Colour USB Save Game Backup, its pretty straightforward once you have the hardware to be fair
So you have a few options on how to save this Mew if you really want to.