I go backpacking as well as car camping. Recently I happened to discover IGBC approved coolers (well, new to me). Most of them are pretty thick walled and require the use of locks to keep the bear proof.
For example, here is a link to Canyon Cooler (I have no affiliation to this company)
https://canyoncoolers.com/collections/hard-coolers
Out of curiosity, I contacted Yosemite NP and they do not allow you to store IGBC coolers outside of your car. Food must be stored in bear proof food containers that the park has installed. There are 2 reasons for this. 1) They require locks to make it bear proof and many people are not compliant and 2) there is nothing to distinguish an IGBC cooler from a regular cooler and people around you will assume leaving coolers out will be OK.
Anyway, I thought that I would pass this along.
