edited jpegs are only 1 mg in size.... originals are around 6 mg

Compression is set at the maximum…. That’s why Im surprised at it being 1 mg or less.
By @michael23321582est1

Where to look for compression or quality ?

When you save a file with the jpeg format selected and you click on the 'save' button, you are presented with a drop box like this:

The more compressed, the smallest size and the lowest quality.

In my example, the original jpeg weighs 3,5 MB.

I can select either the quality from 1 (max compression, lowest quality) to 12 (max quality, lowest or no compression).

Either enter the value or move the slider.

To get an estimate of the expected result, tick the 'preview' box.

As a matter of fact, choosing 11 or 12 outputs a bigger file than the original, even if they create artifacts you can see with a big magnification.

Choosing 8 to 10 generally gives a very good quality result with a reasonable size.

The compression ratio depends also of the type of your image:  grainy or noisy images or images full of foliage details will compress less than blue skies. You can preview the size and then check the quality after saving. The golden advice is never to overwrite the original and never use jpeg except for the last save for print or display. Saving a work in progress requires non destructive formats like .psd or .tiff.