On Pixel devices the only apps that I've noticed this happening on are banking/finance related; I assume that's for security reasons and part of the app design.
This happens pretty much any combination of apps, most of the time.
My favorite is when I am trying to authenticate to a stupid website that stupidly uses SMS-based 2FA.
I will log into the website and it will show me the 2FA input page. I then switch to my SMS app to read/copy the authentication code. When I switch back to the web browser, the state is gone. It tries to reload the same URL but of course that's invalid and the operation fails.
If I were you, I'd try a few different browser apps which don't use WebView until you find one that has proper save/restore of the open web pages to disk.
Moto g8 for a couple of years, now g30. Just works. Can't say I have a lot of apps, though I definitely doesn't have an app for every burger joint down the street.
DDG and FF as browsers.
Go for a non-flagship, less-expensive phone with less RAM, and I expect it happens even more often.
(To be fair, my experience has been similar: on my Pixel 4 I don't have issues like this. But I've seen it happen on older phones in the past.)
Also, any other Android office will not get this. I have a Samsung lying around which basically was useless 2 years after
I only updated to a Pixel 5 last year because the battery was deteriorating after several years and I was given a Pixel 5 for free.
I have never experienced any app resets with the 3 or 5 (aside from banking, which is by design), and I switch between maps, browsers, camera etc. very often.