For me, honestly, its one thing if Sony is blocking crossplay. I somewhat get it (from a certain coldhearted business standpoint)- why give your competition (that would LOVE to put you out of business if they could, despite what they say) the benefit of getting to play with your much larger userbase. As long as your own userbase doesn't complain too much (or wanes) then why would Sony give a fuck. Business is good in Sony-land, so fuck MS and fuck Nintendo.
But, the real shit area here to me is the fact that your Epic account (a 3rd party account, NOTHING to do with Sony) is now affected when its used elsewhere. Your stats, and already purchased cosmetics should not be held hostage. But I guess theres also another aspect. When you buy your Vbucks while on a playstation, PSN gets a cut of the purchase, (as does MS, as does Nitntendo now, I'm sure on their respective storefronts). So obviously, they prefer those people don't start buying those V-bucks at other storefronts. Biut, that's competition for you.
But regardless, anything up to today that you bought, wherever it may have been- Sony has no claim to that. They made their money on it (or not). No reason to say those can't be used on a Switch or an Xbox when Sony does not own that content in the first place. That's where the real pettiness comes in. And honestly, part of me DOES blame Epic here for maybe playing a little bit harder hardball here. It seems to me, they were the ones who fell in line with Sony, as they could have said nope, you don't control our third party account system and how we implement it on other platforms. But they didn't.
I'd even say Epic would have a lot of leverage in this argument. Sony could lose a LOT by not being all in for the biggest player in the battle royale craze. Plus a ton of games (on Sony platforms) use Epic's tech, so they probably don't want ot piss off THAT company. But alas, Epic didn't play hardball & the only way things can change is by it eventually hitting their pocketbook, and there being a noticeable decrease in Vbucks purchases happening on PSN (and major growth happens on Switch/xbox).