I have a 201K which is a great workhorse for most of the sewing for bag making, but it did ‘miss’ a few stitches on the thickest parts (more than 5 or 6 layers) especially when topstitching.
I also have the Janome HD9, which fulfils everything I need it to do - I can sew from 12+ layers of vinyl down to 2 or 3 without it missing a stitch.
The HD9 is perfect for bag making, especially when you don’t have room for an industrial. It is only a straight stitcher, and is a bit noisier than the Singer. There is a Fb page for the HD9.