In case others find this, I think I just found a solution (from this blog post) that lets you force the browser back to showing the Light version of OWA with 40-some messages listed at one line per, instead of the ridiculous modern tile version where you see 4. Directly after the /owa/ part of the URL you are using, paste in ?exsvurl=1&layout=light&wa=wsignin1.0. So if you are getting your webmail on office365, your URL will look like this:

 https://outlook.office365.com/owa/?exsvurl=1&layout=light&wa=wsignin1.0

In case others find this, I think I just found a solution (from this blog post) that lets you force the browser back to showing the Light version of OWA with 40-some messages listed at one line per, instead of the ridiculous modern tile version where you see 4. Directly after the /owa/ part of the URL you are using, paste in ?exsvurl=1&layout=light&wa=wsignin1.0. So if you are getting your webmail on office365, your URL will look like this:

 https://outlook.office365.com/owa/?exsvurl=1&layout=light&wa=wsignin1.0

Edit: Testing it a bit, it seems like the only necessary part of that is ?layout=light ... So try:

https://outlook.office365.com/owa/?layout=light