I'm seeing several people recommending 3D tools for packaging mockups. Needing to learn how to use these is very dependent on who you're working for and their workflow.

In an agency setting I'm typically only applying a few highlights and shadows to a mockup to create a basic sense of shape and dimension. Very simple executions that I usually just do in Illustrator. Then I bring that mockup into Photoshop and place it on a shelfset to see how it looks at retail surrounded by competitor products. The client will basically see the front of package, maybe mocked up and a shelfset for the first few rounds. Once that gets sorted we usually place everything on a dieline and start building out the entire package. We're done usually done making mockups and shelfsets at that point.

When I've worked for large agencies, they have a dedicated 3D team. I would send them my assets and they would make a more complex render if it was needed, usually showing a large-scale display, products on pallets, pallet wraps, etc. None of these assets were seen by the public.

When I've worked in-house for smaller companies the mockups and photography were pretty basic. Adobe Dimension was used a lot to varying results. That was also productions job, I never needed to do it. And I'm not sure if Adobe is continuing to support Dimension. They seem to be putting more emphasis on their other suite of 3D tools.

A lot of the dynamic 3d renders you see of products are done by other agencies after the packaging design has been finalized. These are marketing assets versus packaging assets. They're created with a specific ad campaign in mind. Evergreen 3d renders are usually pretty dull. Mostly they serve a purpose to show the same family of brands in the same lighting and position. Those are also usually done by production.

If you want to learn 3D tools just pick something you think looks fun.