I like your 'different' configuration, and would not change what I've beheld of it.
Utilizing Windows Defender & Firewall, Smart Screen & Sandboxie, marches forth with the precision of a university brass band that leads the "endless" Rose Parade!
My suggestion, from personal experience, is to try portable versions of software including browsers you'd like to test browse!
They would, in fact, be installed on an external flash drive which helps keep your system freer while simultaneously allowing you to replace, experiment, and simply enjoy the latest version of a program. Sending a shortcut to your desktop makes it simpler to open in sandbox too!
Thank you for sharing your choices. I'm feeling inspired now!