If a memory card is not recognize in PS2 Browser basically it means that it's dead.
Although you can try to download and use MC Anihilator v1 CLI (./old/MCA_cli_v1.0.elf)
https://www.cdrinfo.pl/download/8133012839.
To be sure in 100%.
You can also try to recover your card with:
https://www.psx-place.com/resources/...rd-killer.960/.