Is there a wallet you can recommend that allows you to create and fund multiple addresses from a debit card and also assigns a mnemonic seed phrase to each address?
Hmm… There’s no wallet I know of which allows you to directly purchase Bitcoin using a debit card. You’ll need to go via an exchange, like CoinMama.
There’s also no wallet I know of which allows you to assign a seed phrase to each address. This would be a very dangerous practice, due to the way Bitcoin wallets work… Lets say you mined a block and received 12.5 BTC to your address. If you then paid 0.5 BTC to a company, that entire 12.5 BTC would be spent, with 12 BTC returning to a newly and automatically-generated CHANGE address also controlled by your wallet. So, this is one of many reasons why private keys (as represented by seed phrases) are used to control the entire wallet and all its contained addresses.
However, many wallet programs will allow you to generate multiple wallets within them. I know Electrum does this, and you can have a new seed phrase for multiple wallets and swap between them. This would be the recommended practice if you wish to keep different “accounts.”