ETH Stuck on Mantle Main Network

Hi, 63yr old newbie to reddit and crypto here. Can anyone help with this? I'm hoping it's an easy fix!...

I had about 0.3 ETH languishing in Binance and decided it would be better off staked somewhere (I'm new to staking as well btw). After a bit of research, I decided to stake on Mantle so withdrew it all to Metamask wallet. With hindsight I should then have linked my wallet directly with Mantle LST, instead I connected Metamask wallet directly to Mantle mainnet via Mantle Bridge - intending to stake it from there. The transaction went through OK, it's recorded on Etherscan, and I got the 4MNT dusting back in my Metamask wallet. Problem is I can't access it now. I can see the balance (when I connect Metamask)....how do I either stake it on Mantle?...or withdraw it back to Metamask and start again? When I try the latter, it says there is a discrepancy in the networks.

I've run out of ideas (albeit, very limited!). Any advice would be greatly appreciated.