Depends what do you want to do. I assume that if you want only check the balance is would be simpler to convert seeds into addresses (depending how many addresses you want to generate and for which derivation path) and import them into single watch-only wallet.
Most wallets won't like importing a couple hundred thousand addresses.
Just interested to know, why or how did you get even those 10,000 wallets? LOL
Maybe he has a very successful phishing site.
Or he randomly generated 10,000 seed phrases and now wants to see if he founds someone's wallet. If that's the case, it's a massive waste of time.
I hope you didn't pay for those. If you did, then you were probably scammed.
Or that. I can't think of any legit reason why someone would have that many different
used seed phrases.