Here's the thing about Persona 3 Reload: it's not all of Persona 3. In particular, the remake is missing the epilogue campaign—called The Answer—that came with Persona 3 FES back on the PS2, and it's missing the female protagonist you could play as in the PSP (and now PC) version of the game, Persona 3 Portable.
All of that sounds like a great excuse for Atlus to put out a Persona 5 Royal/Persona 4 Golden-style reissue of the game somewhere down the line, selling you the game again in the form of a version that comes with those currently missing pieces plugged in.
But apparently the studio is breaking the habit of a lifetime, because Persona Team production manager Kazuhisa Wada recently told Gamerwk (translated by Persona Central) that Atlus is currently "not considering a revision like with Persona 5 to Persona 5 Royal" for Persona 3 Reload. "Fans can rest assured knowing that Persona 3 Reload offers a complete experience," said Wada.
It's a bit of a surprise: Atlus has released beefed-up, director's cut versions of every mainline Persona game since, well, 3, but it seems like the company isn't going that route with P3R. Unconfirmed leaks are floating about that Atlus has a fair amount of DLC in mind for the game, though, so with any luck those will hold true and we'll still get The Answer at some point. Just not in the form of Persona 3 Reload: Royal: Golden: Origins: Bloodlines.
As for the female protagonist? I'm less certain. It'd be an awful lot of work entailing new social links, cutscenes, animations, and even a whole new UI. It's the kind of thing that maybe you'd do if you were re-releasing the entire game, but as a single piece of DLC? It sounds unlikely. I'll keep my fingers crossed, though; Persona 3's femPC is a fan staple for a reason, and had some of the best social links in the older versions of the game.