Try Vivaldi. It's a "kitchen sink" browser in the same vein as Opera used to be back in its days of glory, so it comes with an email and calendar client that can be optionally turned off:

https://vivaldi.com/blog/vivaldi-mail-calendar-feed-reader-a...

But you can also just use it as an email client and ignore the browser part.

Vivaldi's email client is kinda clunky as well and has no way to show just my "inbox" (mail without any labels) from Google as far as I can tell, just one big unread chunk. And the calendar seems to just be a column on the left of the browser.

Either way, MailSpring works fine for email, and I've recently discovered Fantastical for a straightforward calendar program.

But it's absurd that I have to do this at all. At a minimum, if I buy a laptop, Microsoft should not be able to actively break it without refunding me 100% of the purchase price.

The Vivaldi web browser tab groups are a killer feature. It's my main browser because of this.