The article is from July 2nd, I only saw it now thanks to Rhea sharing it. Heartstopper season 3 is talked about briefly but it's vague enough that I know I won't have a use for the quote once the show is out so I put this in the other Heartstopper adjacent links list. This is what Rhea said about Heartstopper season 3:
"All the characters are much older now. They’re exploring A-levels and what it is to maybe go off to university soon. There’s definitely some harder themes that are tackled in Season 3. But it happens through this really wonderful ‘Heartstopper’ lens where you get hugged with it, as well as some of the tricky things that need to be talked about."