If in any case, you're still in good fortune since you have the private key of your wallet. You can use a wallet like CoinOMI for one, or those wallets that use private keys, just put that into the site and you should be good to go.
Keep trying using the private key on different dogecoin wallets, you can also try from versions made during the time you created the account,,, It should work for coinomi though. Maybe try the old version of Exodus wallet? They used to support DOGE but that was several years ago. Private keys for doge should work in any decent wallet though,,,
Exactly, constant trial and error should do the trick since you have the private keys anyway. It shouldn't lock you out permanently because technically, you have the tool to unlock it.