Ever since Gmail redesigned its UI and Inbox app has been killed, have been looking to make the Gmail look less complicated, just to be able to see the emails without all lot of bells and whistles, found a great chrome extension, thought may be useful to Anker Forum members - Its called Simplify Gmail (… yes, its literally called Simplify 
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Link to Chrome Store is here
There is a good article on mashable if you are interested to know more.
I use just Gmail. It’s well updated and on pie/Samsung one UI.
I can’t say the mobile app is complicated or anyworse than previous versions.
I’ve never used INBOX, so can’t say about that.
My only real niggle on Gmail app, is not easy to change/delete/create labels. You have to go to desktop mode to do anything, despite there being a “manage labels” in the settings… You can’t actually manage labels there.
I use the email app that came preinstalled ony phone. Or the website version instead of Gmail’s own app
For iOS mobile, Gmail app is the best one, but the web app for browser is complicated… this extension simplifies it
Inbox by Gmail was quite popular and liked on Android but it got shutdown recently. But yea, I’ll just stick to the web page. But I’m sure others will find the extension you posted useful 
I used Inbox but had to switch back 
Inbox was one of few good applications which Google has killed… still missing the simple interface. Gmail has got the swipes now, but still not like the Inbox
Always used email built in phone and chrome for computer to access gmail. Never used inbox.
I use an app called Edison (iOS) not sure if it’s on Play Store. I would assume it is.
Multiple accounts, merged inbox. It’s amazing.