Have you used iPadOS 26 or better yet Stage Manager? You can have as many Split View apps setup similar to that of iPadOS 18.
I only really turn on stage manger when we start chatting about this because otherwise its limitations bug me too much.
However,
"as many Split View groups as I want" was in reference to the new resizable multitasking windows system in iPadOS26 (in which you only have one "space/desktop" into which you can place resizable windows) I wasn't referring to Stage Manager with this remark.
With the new windowing system they supposedly gave people what they wanted but still failed to achieve the level of capability that was present back in 2005 with Mac OS X Tiger... (Panther didn't have spaces so I guess they sort of matched Panther but worse? because its harder to drag and drop windows form the fullscreen area into the resizable area?).
/s Such progress and innovation, they managed to sort of badly replicate something that was possible on an iMac G3 running at 233 MHz ... there is no excuse for the limits on running apps or the number of windows given what was possible 22 years ago...
Stage manager is better than this new system in this regard because you can have spaces/desktops to work with but it still limits you to only
easily working with 4 spaces.
The recent apps area is so limited when you could achieve nearly the same thing with more flexibility with a drag and drop global App Exposé system.
User can have stages (Recent App area) with multiple SplitView apps. Once again you bring up Exposé when I informed awhile back that under the new system you multitask via the Recent App area.
You and I obviously differ on this but I find the recent apps version of window management inferior to the broader global app switcher.
The global app switcher (with Split View) lets you drag apps between Split View groups, fullscreen windows, and slide-over. It also lets you do this for apps that are arbitrarily in the past rather being limited to the 4 most recent app groups. Stage Manager (for some inexplicable reason) doesn't let you do this, it forces you to use the much more limited and restricted recent apps switcher.
If you are accustomed to using macOS… spaces is similar to that of Stage Manager whereas you have multiple windows/apps within a stage. You can have Messages, Discord and WhatsApp within a stage.. then maybe Safari, Mail and Google Keep within another stage.
Stage manager does do this, but as I've said, it has arbitrary and weird limitations such as stacking (see below) its much more fiddly than Split View since StageManager requires more precision in placing the windows to get a nice Split View (again macOS somehow supports both resizable windows and Split View - I actually use macOS the way you are recommending stage manager be used here precisely because macOS doesn't support drag and drop
out of a Split View or fullscreen).
Not sure what you mean by stacking here?
Open 5-7 safari windows in fullscreen with Stage Manger enabled - they will be stacked on top of each other making it difficult to impossible to grab windows from anywhere but the top of the stack. This isn't a problem in macOS anymore (since they gave us the option to turn that idiocy off) nor is it a problem in iPadOS 18s SplitView style App Exposé multitasking system.
Given my brief time with iPadOS 26's resizable multitasking system I'd rather use stage manager than that as it at least (as you say) gives you multiple desktops for better organization.
I'm not saying Stage Manager is not useful, what I'm trying to say is Apple has spent years and has yet to manage to replicate the easy to understand mental model that they first mastered 20 years ago with Mac OS Tiger ... with Tiger (and iPadOS 18 in Split View mode) you can mentally conceptualize where your windows are, it is predictable, it is easy to manipulate.