you wouldn't want to store large amounts anyway.. just so you can make/receive payments with privacy in mind.. 12 word seeds are not stored anywhere.. scan and spend secret keys are encrypted and if your session is compromised so can be the keys... not easy either for the attacker..

Thrilled to announce Thrilla - #SilentPayments #Bitcoin wallet harnessing the power od #LnBits and #BlindBit indexer. Self-custodial as keys stored in local storage on the browser. Check it out at: https://thrilla.me

You can self host it with BlindBit set of tools, both scanner and indexer: https://github.com/setavenger/blindbit-scan/tree/master