The Dollar Store sells Sunbeam very inexpensive Super Heavy Duty batteries from "over there". They are labelled carbon zinc the same as batteries were 50 years ago.
This website
https://michaelbluejay.com/batteries/disposable.html lists all the disposable batteries and says:
(SUPER) HEAVY DUTY. These use the newer method, Zinc Chloride, which offers 2-3x the capacity of Leclanché batteries, better performance at lower temperatures, and are less prone to leaking. They were "Heavy Duty" compared to Leclanché batteries when they were introduced decades ago, but compared to modern batteries, "Heavy Duty" are really "Super Extremely Light Duty". Leclanché batteries are ordinary old carbon zinc.
Most Super Heavy Duty batteries listed on ebay say Carbon Zinc.
I watched a test of 8 AAA batteries on You Tube. Super Heavy duty and Alkaline. The testers were toy cars.
One Super Heavy Duty failed at half an hour.
Another Super heavy duty lasted about 1 hour.
Duracell Alkaline failed, then Harbour Freight Alkaline then Energizer Alkaline then Rayovac alkaline then a no-name-brand Alkaline.
The Sunbeam Chinese Alkaline from The Dollar Store beat them all lasting almost 9 hours.