I went down the same rabbit hole earlier in the year.

There is some wattage savings but honestly, an aero helmet provides marginal gains. Learning to ride in the drops or the aero position more often would net more gains. Specialized and GCN has some YouTube videos exploring these topics.

I personally bought a Limar Air Speed and enjoy it more for the features than the aero gains. It has a sunglass dock, magnetic buckle and since it has less vents, keeps the noggin a bit warmer on early morning rides.

If you just want an excuse to upgrade or treat yourself, find something that fits, looks good and makes you feel better about riding. Whatever keeps you happy out on the road.