你說的可能說對的，457b是分開的 not sure about 401(a),

 at least for 401(k)/403(b), the limit must be aggregated per your link:
"The amount you can defer (including pre-tax and Roth contributions) to all your plans (401(k), 403(b), SIMPLE plans, SARSEP, not including 457(b) plans) is $23,000 in 2024...  the total amount allowed under the tax law doesn’t depend on how many plans you belong to or who sponsors those plans."