

Regarding the future uniforms, the same uniforms appear in most portrayals of “future starfleet” during the TNG era, such as DS9 The Visitor. I don’t believe they are meant to indicate a connection between alternate futures beyond being the next step for Starfleet uniform designs (although the uniforms shown for a similar time period in Picard turn out to be different anyway).
Regarding your question more broadly, yes. And also no. Both, really.
I’m not sure Q recognizes or cares about the distinction between spinning up an entirely bespoke simulated reality for Picard to do his thing in, versus altering the past such that branching timelines are created and shuttling Picard’s consciousness between them before ultimately closing them off. Or whatever other myriad mechanisms an omnipotent being would have for triggering the events portrayed. Nor is there any real way for us the viewer or Picard the participant to distinguish between those things. What is real, what clearly matters both to Picard and to Q, is that Picard did pass a test, and that Picard remembers those events in a way which will influence his future actions and relationships.
I’ll stand by the position that the Enterprise augment virus arc was an error, and the “explanation” for Klingon ridges is the same one you should use for the bridge of the Enterprise looking like it was cobbled together from plywood and plastic beads. This issue was best left to Worf’s lampshade in DS9 Trials & Tribleations.
It’s really interesting which visual differences humans will accept unthinkingly and which we will demand answers for. The Klingon ridges thing comes up constantly, but I have yet to see anyone earnestly ask why all the characters in Lower Decks have huge eyes and unnaturally uniform coloration, or why hand phaser beams in TOS go so much more slowly than later phasers and why everyone agrees to stay really still while they are being fired.