I've been using Boxy since Boxy for Inbox. As soon as they released Boxy Suite I bought a lifetime licence.
I'm a huga fan and really recommend this product to anyone who frequently use the Google products they cover.
The only complaint is the coloring of the dark mode theme actually. But you can change most of that in Gmail so it's fine for now :)
Great for productivity
Love the "app" feeling instead of having multiple tabs open
Awesome additions on-top of the normal feature-set
The dark mode is "too dark".
Dark mode in Gmail doesn't always work as most things sent by mail is designed for a light background.