Need help with Bitcoin Core ver 25.1.0 and wallet restore

Hey there everyone!

I am running the latest version of Bitcoin Core (25.1.0), and just finished syncronizing the whole blockchain, worth about 560 gigs of data. Every time I open the application it says I am 40 hs behind (even though it fully synced). I am using a 2tb NVME so lack of space is out of the question.

What I really need to do is restore my wallet.dat file to perform a transaction but something's off with the app.

Aside of the weird stnc thing, everything takes forever, even creating a new wallet...which ends up in a loop (never waited for more than 5 minutes).

I read somewhere that you can use your backed up wallet on online wallets, does anyone onow how to do it and which wallet would be the most recommended for this purpose?

Or, how to fix my Bitcoin core instance.

Thank you very much in advance!