Iphone pictures: JPG from USB vs JPG from icloud(web) vs JPG from icloud(pc app)

Hallo everyone,

i am the owner of an iphone8 and i am a little confused on how apple manages JPG files.

On settings->camera->formats, i am using high efficiency setting, which means that the iphone is storing pictures in HEIF format. Now, if i download the photos from usb or icloud(web) or icloud(pc app) in HEIC container, they will all have exact the same characteristics. Same pixels, same bit depth, same size etc.

From the other hand if i wish to download the same pictures in JPG container, from the same sources, they will be completly diffrent!

Here is an examle:

i have the picture ''IMG_4004.HEIC'' at 943KB, with 32 Bit depth and 3024x4032 pixels. This picture downloads the same, from all sources (USB, icloud(web), icloud(pc app)). But, here it is in JPG container, from the same sources accordingly:

USB: ''IMG_4004.JPG'' at 2.76MB, with 24 Bit depth and 3024x4032 pixels

icloud(web): ''IMG_4004.JPG'' at 491KB, with 24 Bit depth and 1536x2048 pixels

icloud(pc app): ''IMG_4004.JPG'' at 1.66MB, with 24 Bit depth and 3024x4032 pixels

It seems that apple is using diffrent algorithms to convert pictures from HEIF to JPG.

So my question is:

Which JPG file is better in quality terms?