Your spouse can contribute to an HSA to if they had their own high-deductible health plan. If your insurance plan is a high-deductible health plan, you can contribute to an HSA for them either through your employer or a separately purchased HSA.
Contributions to a SEP IRA are limited to 25% of your spouse's net income, up to $69,000 for 2024 ($70,000 for 2025).