This sounds new to me, that people take the risk of saving wallet seed phrase with an online platform???
As I started reading the contents of your post beginning from the topic, I was wondering if it is now something bad to store passwords and codes with an online manager. Because I am a big fan of storing passwords with google. But reading down, I comprehended the motive of your post. And right now I'm still wondering how could users possibly trust a platform to the level of saving his/her wallet seed phrase with them. There's a statement some crypto enthusiasts around me always say and it goes "Never Disclose your Wallet Seed phrase to Anybody"
Saving wallet seed phrase with an online platform, I see it a form of laziness.
No matter how a wallet seems useless to me, I always write down my seed phrase and keep it somewhere very safe and secured how much more a wallet that contains something tangible.
Your concern is justified, saving mnemonic phrases or WIF private keys in online managers has a high chance of being rekt.
I recommend stopping using browser password managers, although they've evolved over time, they still cannot compare to the security of an offline password manager like keepass, which works even without an internet connection, since the database is saved locally.
Offline password managers have strong encryption such as AES, ChaCha20, etc. So you can save anything there, not only passwords, but OTP codes, attachments including images, files and texts.
It is better to encrypt the mnemonic phrase in a keepass database in an air-gapped offline environment. It's much safer than leaving it in online password managers or scattered around unencrypted.