I don't think I saw it in the article but in "Flash and Substance," Flash did mention his uncle was flying in. I figured that was an allusion to Barry and like the Hal Jordan of the DCAU (well at least initially), led a normal life so perhaps he lived elsewhere out of state. I figured either he stayed in/moved back to his home town of Fallville, Iowa or remained in the city he went to college, Sun City in Florida per his origins in the comics...er Silver Age I believe. Hence, he would take a flight to Central City though for the former I guess he could have drove. So Wally's supervisor in the episode was, imo, just a visual nod to Barry.
You can have more than one uncle. In fact, Wally also mentioned his mom in that scene and, in the comics, they are not close. I suspect that the writer took some creative liberties with Wally's family tree.
I also didn't mention Flash's "Grammy Flash" in the article either, though I suspect that the reference is more of a DC version of the Thing's "Aunt Petunia."
I don't think that necessarily negates the legacy aspect because the impact the past Flashes had, past and present, can still have an impact on the present-day Flash and still learn from them

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But I love Jay and Barry so I'm probably biased

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Kind of reminds me that of all the "Archenemies" they only managed to work in a Reverse-Flash at the last minute when the Luthor/Brainiac fusion came up with Justice Lord Flash on the fly.
Hey, I like Jay. He's been a solid supporting character in the various "Justice Society" titles, but DC Comics kind of has a problem with too many heroes going by the same name. At various times, there's been two Supermans (I'm excluding
Reign of the Supermen, where there were five), two Batmans, three Flashes, two Wildcats, two Atoms, etc. The only hero there should be multiples of is Green Lantern because it's built into the mythos. And then there's Alan Scott -- I really wish DC would just retroactively make him a Corps member too.
Even Marvel Comics has two Captain Americas now. There's dozens of Spider-Mans (thanks, Spider-Verse!). Legacy is fine, but too many heroes dilute the brand.
Barry, on the other hand, I can take or leave. He was great as a martyr, but bringing him back and giving him a "modern" origin left me cold. Wally's my guy.
And, yeah, the creative team never did bring in Reverse-Flash / Zoom / whatever you want to call him, but I think Grodd qualifies as Flash's archfoe on the series, even if they didn't cross swords all that often. Series-wise, Grodd is convinced that he's destined for greatness, while Wally doesn't care and just goes with the flow. Grodd probably cannot stand the fact that a gimmick hero dumber than him is better loved and victorious more often than he is.