I'm just presenting an argument for how it could happen in both timelines to make it consistent with what we saw in Star Trek (2009).
Obviously that's what you're doing. The point is that we no longer
need to. If the novels have to be seen as an alternate timeline anyway, then that means it's no longer a requirement for them to converge with the events established in the movie. And my point is that it would make more sense now if they didn't, given the new information
Picard has established.
The primary reason I was interested in seeing that in the novel-verse is that we've seen the Romulans have a moderating influence on the Typhon Pact, preferring diplomacy when dealing with the Khitomer allies. What would happen if you take Romulus out of that? I'd think it likely the Breen, Tzenkethi and Tholians would try to fill the vacuum and in the books we've seen they'd prefer a more hostile stance. So I could see some dramatic future stories with Romulus being destroyed.
I think
Picard has already addressed the consequences of the Romulan Star Empire's removal from the galactic stage. Doing it in the Typhon Pact continuity would differ in detail, but in broad strokes that story has already been taken up by the show. So maybe it would be more interesting to explore the alternative path history might've taken without the supernova, without the fall of Romulus.
And the other thing is the Federation by 2387 is in a better place in the novels than in Picard. I'd be curious to see how that Federation deals with the disaster in comparison to Picard.
Is it? It's still recovering from a cataclysmic Borg invasion that the canonical universe was spared. If anything, it's a lot worse off, a lot more depleted in resources. In
Picard, it's the evacuation effort itself that's eaten up so many of Starfleet's resources by the time of the Utopia Planitia attack in 2386. But all the UFP's worlds are still intact, there aren't billions of refugees already within Federation space, etc. I'd say that from a material and logistical standpoint, as well as a psychological standpoint, the novels' UFP is
far worse off, far more beaten down by catastrophe after catastrophe (the Genesis Wave, two or three Borg invasions, a presidential assassination, etc.), than the canonical UFP.
So really, having the supernova happen in the Pact continuity seems redundant. Both continuities have their own vast cataclysms and immense refugee crises starting c. 2381, one caused by the Borg, the other by the impending supernova. Don't forget, the Typhon Pact arose as a direct
result of the Borg invasion. The TP narrative is already about how Alpha/Beta Quadrant civilization is changed in the aftermath of a transformative cataclysm.
And come on. Star Trek loves contrivances

---it would not be the first....or last time.
The fact that a bad idea has already been used multiple times is an argument
against doing it again, not in favor.