I don’t see a specific rule for this, but I would just let them ignore the restriction of picking a certain number of archetype feats before selecting a new archetype. There’s nothing preventing you from picking a 2nd level feat at level 4.

https://2e.aonprd.com/Rules.aspx?ID=1333

I enjoy it. Even if I don’t plan on running the adventures he reviews, I’ll watch them just for the entertainment value.

Pathfinder 2e didn’t work out well in my main group, so Ive started running Abomination Vaults for my kids. It’s a lot of fun but the younger ones drop in and out, so my oldest ends up running all 3 sometimes.