Yes, but my current understanding is that these minerals are in very miniscule amount, like 1% RDA a cup. You are able to remineralize after RO, automatically as part of the system, if you would like. I don’t, because I already supplement magnesium and calcium levels aren’t a typical concern.
I think the trade off is well worth it to ensure there’s no lead, plastic, hormones, or hexavalent chromium at all.
Cost is around ~$300 initial, $50/yr filters, and maybe $5/yr increased water usage.