I don't do any finance with Google or Microsoft, I def don't give any health info to Microsoft, I use degoogled browsers, so I don't think they are able to grab any URLs/searches(or if they do, its clear they arent current matching anything to my main account).
Every company gets a little bit of information, where as, I'm suggesting that in this particular case, 1 company gets everything.
But in terms of using those platforms - you likely log into your bank via a chrome-based browser or Edge.
Even if not, you are still running a browser on their platform. Why not scrape financial information from another source such as disk storage or by monitoring network/crypto API?
If the platform vendor turns malicious, why presuppose they will only alter the behavior with respect to their own apps?
Every company gets a little bit of information, where as, I'm suggesting that in this particular case, 1 company gets everything.