I have a private key, how do I access funds?

I bought some land in The Sandbox a few years ago, then sold it via Open Sea, and the funds have been sat in my Bitski Wallet since.

I’ve only just remembered and gone on to Bitski to see what’s there…and discovered Bitski no longer exists!! Apparently they sent e-mails out to users, but mine must have ended up in spam as I had no idea.

I have my private key to the Bitski wallet, but I’m absolutely clueless about what I can now do with that? How can I use the private key to gain access to my funds? Or has it all been lost?