I am not familiar enough with the Wars of the Roses part of the Histories to be much help there, I only really know the Henriad. Might want to talk to @reeve-of-caerwyn , who is another hardcore Yorkist. My suggestion would be… just watch/read the plays and cheer on the House of York?
(I’m a hardcore Orléanist, so this is reallllly not my circus and monkeys).
Yeah I don’t really see why you can’t read the H6 plays as a Yorkist. They aren’t as biased as you think. The first one (1H6) isn’t even about the Wars of the Roses, it’s about the Hundred Year’s War primarily.
But the next two plays are pretty neutral and everyone (on both sides) in them is kind of an asshole, but it’s made out to be a violent time and a time where everyone is just doing the best they can for their families.
In R3 Richard is obviously the bad guy but I don’t see what that has to do with the house of York proper, and E4 is made out to be a good king.
The idea that a hardcore Yorkist wouldn’t enjoy the Henry VIs in general is ultimately rooted in the idea of the history plays as Tudor propaganda. Shakespeare’s primary goal wasn’t, especially in the 1590s, to uphold the legitimacy of the Tudor dynasty; that was done and dusted, and indeed the Tudors were on their way out since Elizabeth was in her sixties and childless. He’s much more interested in larger political issues: what happens when there isn’t a clear succession, how civil strife can tear a country apart, what makes someone a good or bad ruler, what does this whole “legitimacy” thing even mean? These are much more universal issues than which particular set of Plantagenets deserved to wear the crown, and issues that could potentially arise again in the very near future, and Shakespeare’s just using history to examine them. Which is what history, certainly in the ideas of the period, is for – early modern readers looked to history for examples and precedents. The sources he was using had a certain amount of bias (I mean, all history does, to an extent) but he was less interested in advancing particular dynastic claims than in the bigger picture. And indeed, the only side Shakespeare really takes in the history plays is England over France (not without a grain of salt, but ykwim). The conflicts between Richard II and Henry IV, Henry IV and the Percy faction, and indeed Yorkists and Lancastrians are all depicted in various shades of grey; few characters are entirely heroic or villainous. (Richard III himself was already an accepted historical villain by the time Shakespeare was writing, although that version of him has survived to the present day entirely because of Shakespeare. He probably didn’t have much access to an alternate historical tradition.)
This is, of course, because Shakespeare was a humane and nuanced writer, but he was also participating in a deeply anxious tradition in his treatment of the Wars of the Roses. The entire period from Richard II to Richard III was thorny ground for historians of Shakespeare’s day, because the state and the church together sought to promulgate a very particular interpretation of it: that the deposition of Richard II was a sort of dynastic original sin that led to civil strife in the reigns of Henries IV and VI which was then punished eventually by the tyranny of Richard III as a sort of “scourge of God” and then redeemed by the Glorious Coming of the Tudors. And also that any kind of rebellion was itself the worst sin you could commit, worse than the worst ruler ever and basically mirroring the sin of Satan – this idea had taken off in Protestant circles because it emphasized king and not pope as the highest earthly authority. Probably the most famous attempt at the Authorized Tudor Version of the Wars of the Roses (and also an earlyish use of the rose imagery, on its delightfully wacky frontispiece) is Edward Hall’s Union of the Two Noble and Illustre Famelies of Yorke and Lancastre (first published in 1548, shortly after the death of Henry VIII).
Except that there were a couple of teeny little problems. One is that Henry IV is actually a pretty pivotal figure in the Lancastrian claim to the throne; the Tudor claim comes not through Henry himself (whose direct line of descent died out with Henry VI) but through his father, John of Gaunt, via the formerly-bastard Beaufort line. Henry IV had had his half-siblings barred from the line of succession, an act which Henry VII undid, but he’s an important piece of the puzzle all the same on the grounds that he put the line of Gaunt on the throne. So while the Tudor theory of monarchy depends on Richard II’s legitimacy (which was unquestionable), Henry VII’s actual claim to the throne required Henry IV’s legitimacy as well (Henry VIII and following inherited the Yorkist claim from Elizabeth so it was less of an issue). And if they could both be legitimate – if it were possible to earn one’s legitimacy through one’s actions, as the poet Samuel Daniel suggests Henry IV did by winning at Shrewsbury – well, that is good for Henry VII and his descendants on the one hand, as it validates his claim by virtue of being the last man standing, but it also suggests fairly strongly that even if your bloodlines aren’t the closest to the throne, you can become a legitimate ruler if you can get and hold onto the crown. And you wouldn’t want to suggest that. So while the “official” version of the Wars of the Roses looks neat and tidy, it doesn’t really hold up if you look at it closely. (It’s like the Monet of historical interpretation!) And most Elizabethan (and earlier) writers who took it on ran into difficulty on those grounds.
Probably the most concise version of it, though, is the frontispiece from this 1641 history:
That’s Richard II on the left, obviously; the Roman-looking guy on the right is a heavily-idealized Henry VII. In the middle, a big pile of corpses.
@shredsandpatches has basically said it all, but I do want to add that Henry VII is a complete nonentity in Shakespeare’s Richard III. He is The Most Boring.
Also, it’s worth pointing out that Richard III ends on a conditional.
Now civil wounds are stopp’d, peace lives again:
That she may long live here, God say amen!
Which is all to say that, whatever early critics may have said, Shakespeare is absolutely not writing unalloyed Tudor propaganda.