I agree. I too have one Gmail for work and another for personal. Separating the work Gmail is a good idea and I do that on Mac desktop (Outlook for work Gmail mostly for the recipients, and stock Mail App for the rest including a personal Gmail). As you say, the font is too small in the Gmail app but I might try it in my iPhone to see if there might be any convincing benefits. Sure push is critical in work mail.
Actually, the biggest advantage of using the mobile Outlook to me is that you can call up any mailboxes of all accounts in one viewer pane. This may not be too good on a desktop application, but for a mobile phone when you quickly glance incoming email or search archive and send short response etc, this is actually an advantage IMO.
For desktop, be aware of the server side rollouts, and that your organization or administrator might not be on the fast track or standard release. Mac and Windows Outlook have the new features and look now. The web version should now or soon show a slider switch to move from old to new look.
Outlook mobile is good about multiple accounts and display but I mostly like it if at all for work calendar integration. The stock app handles dates well but takes you to a different app.
Google has announced the new mail but I haven’t yet seen it in my phone updates.
I tend to stick with simple if a default app works. Mail is mail. The stock app handles multiple accounts, multiple server types, and manages messages. Innovation and better mouse traps for work are not mail. That’s Microsoft Teams, Slack, and maybe some day Google’s chat will not be so ridiculously lame if compared to Microsoft and Slack.
I don’t expect much innovation with mail just because it’s connecctionless vs chat, uses old protocols, and does not facilitate good collaboration the way Microsoft Teams and Slack do. Mail for work groups is stupid. You mostly multiply files instead of collaborate on same. You can have forked and missed conversations.