thats weird indeed
something is wrong with your electrum wallet for sure.
can you share an address with a balance?
if you right click on your wallet (electrum one) and select open with "Notepad" do you see that address there
also from where do you have wallet.dat? i have read the full topic but didnt understood what that file has to do with your electrum wallet file which doesnt contain the extension .dat
did you name your wallet "wallet.dat" when you have created it in electrum?
Initially, since the creation of my electrum wallet, I used only the wallet.dat file when opening electrum, I never opened my wallet on an old laptop using a seed or a private key, after transferring my electrum folder with blockchain headers files. wallet.dat and others that I described earlier on a new computer, it began to give these errors, yes, I called my wallet like that, yesterday I tried to restore it again as they wrote here using btc core and it just can’t be read, I never used this file in other wallets, I only used it in electrum. I can rename it whatever I want.