I personally use Rambox (https://rambox.pro/) instead of Franz these days, or just click the "install as app" button in my browser.

Really, I see little value over these browsers with vertically stacked tabs. There's already free solutions out there, what's the added value? Workspaces are easy to replicate using Firefox's containerised tabs and the vertical tab structure can be replicated with something like Tree Style Tabs. The remaining minor improvements are nice to have but certainly not worth $20 in my opinion.