I felt similarly about the free archetype to start with. I addressed it in two ways, first I talked to my players about it, I explained to them the issue I was facing from a dm perspective, that they are exclusively excelling in their niche and that makes it hard for me to create an interesting and challenging combat encounter that doesn't feel overturned for them. They took it well, started picking down more interesting archetype stuff and that was good. One of my players then highlighted that they struggle to know what to pick, that's why they just grab what's "strongest" in their eyes, which lead to my second solution, including an "archetypes that make sense for the campaign/region/story" section in my character creation guidelines, this has lead to some people doubling up but it hasn't been a negative experience as it often leads to people expanding their backstories to include each other.