Hi!
I believe wallet.dat files are related to zcash full node, not Zecwallet lite.
Maybe this topic is more relevant for your issue: Restore old 2018/19 Wallet.dat with Zcash Node
But if you’re refering to the file zecwallet-light-wallet.dat, maybe you can use this zecwallet-lite version: Zecwallet lite with Nu6 + zip317 support