Mobile phone as signer
I just had another thought of something that might be interesting to add as it is generally not recommended to enter a seed on a website. What about using the mobile app as sort of Ledger and the website only as frontend.
The website acts as frontend and if you want to do a transaction you can trigger it on the website but you need to sign it on the mobile phone where the key is stored. This is also how banking apps handle their 2FA as they require you to confirm every transaction in a separate mobile app.
Now this would mean you don't need to enter a seed on a website but you can use all advantages of the website.
2FA with mobile phone is technically possible and this has been already discussed once somewhere in the chat. However, such functionality will require a lot of time and work, and is not currently in our priority, so we will keep it in mind, but without strong user demand I would't expect it any time soon.