Open there own a HSA even if covered by your plan. Probable a good savings option as well if maximizing ROTH.

According to AI

" Yes, an adult child can open their own Health Savings Account (HSA) while still being covered by their parents' high-deductible health plan (HDHP). In fact, it can be beneficial for children to open an HSA while they're still young to help prepare them for medical emergencies and enrolling in their own HDHP. "