I agree regarding SSD, I do a lot of graphics development and having to deal with decorations on your own is really annoying. However, most windowing libraries support them nowadays. (GLFW has an open MR to include Libdecor)
The lack of customization has been a decision they made in favor of Libadwaita. Libadwaita is a GTK4 library that makes developing apps for Gnome way faster. The Gnome ecosystem has really evolved in the last two years thanks to Libadwaita, there are so many nicely designed and practical apps. This is the trade-off I am willing to make. For me, a uniform and consistent desktop is way more important than theming, especially when apps look amazing by default.
I don’t get what basic features are missing. I have been using Gnome for years now, I never felt the need for an additional feature. A system tray is not a „basic feature“, as I said, not every desktop has to be a Windows clone. I have never felt the need for one, if I need an app, I just launch it. Why do I have to have a bunch of cluttered and ugly icons visible all the time? An app can run in the background without a system tray by the way.
You are aware that Manjaro ships a heavily modified version of Gnome (lots of theming-stuff and extensions)? You should try vanilla Gnome (eg. on Fedora/Arch/VanillaOS) or try disabling everything.