For bitcoin there is Bitcoin Core which downloads the whole blockchain a few hundred gigabytes then you can use the wallet.
For Ethereum, there used to be a wallet. I have done a backup of the key stores but now I am trying to download that classic wallet but I can't find a download link.
The only nearest thing I found was MyEtherWallet (MEW) but then there is no Download button anywhere on their website, and even whien i try the software version it says Not recommended:
https://www.myetherwallet.com/access-my-walletAny help how to get access to a wallet using the backup keystores from the "old"/"classic" wallet?
The reason why the Ethereun MEW dont recommended or provided the link to keystores is because of ig vulnerability and most ETH mew user have lost their holding through it.
If your situation was about creating a keystroke will advise you to follow this
link but if you're trying to log into your old ETH wallet, you can find your wallet private keys inside the keystroke files import it through Metamask.