I wonder if this is a generational thing. If there's a decent app for a thing, I use the app¹. In this case Outlook. I have 4 email addresses to manage my personal email, throw-away registrations, website comms, and website SSL/admin.
I never access any email ever from a browser - Outlook is unbelievably good, and with the .PST file size restrictions no longer being restrictions I have my entire email archive of ever in it. Been doing things like this since 2002.
¹ Social media is the exception. Where I have multiple social media accounts (Instagram) I use seperate browsers (Edge for hobby account, Firefox for personal account). This is not ideal but the workflow is easy.