(Moving the conversation here as it's flag related)
Assuming the revolutionary flags of la Plata are similar to OTL - blues with stars for what became Paraguay and Chile, blue white tricolour for Buenos Aires/Argentina - then the larger Argentina probably still uses the tricolour plus sun of may. With different shades of blue at different times and for different uses.
I then see the later federal Patagonian flag as simply adding a stripe:
View attachment 494183
Whether all blue,
View attachment 494184
Light blue to represent original core Argentina, or
View attachment 494185
Red if perhaps the the later tricolours of Paraguay and Chile were in use.
(NB on phone so no access to using actual Sun of May image!)
Those are good ideas, don't get me wrong! Though admittedly, the older version seemed like a good idea at the time. I might have to redo some of the recent maps if I'm going to incorporate them.