The most not caveat is we don’t know how much gravity is how necessary. We know that microgravity in orbit is too little and not really sustainable. Is gravity on the moon enough more for long term health? Is that on Mars? That’s just two of the questions we can’t know until we get there

Settlers routinely sacrifice their health to be part of the first wave of people to stake a claim on fresh territories, considering how insane that got during more or less every colonization effort in past history I strongly doubt that harming human health will be a barrier to the whole thing, for better or worse. (I think mostly for worse tbqh, but I still see it happening unless climate change ruins everything, or nuclear war, etc)

So you build spinning space stations instead of settlements on the martian or lunar surface. Likely close to the same material cost, if not cheaper, while allowing us to actually choose the amount of gravity to generate. We don’t know if martian or lunar gravity would even be sufficient to avoid negative health affects.