I pieced and quilted solely on my Janome Magnolia 7318 for many years before I lucked into a used Janome 7700 which came with the convertible FMQ foot. On my 7318, I use a generic walking foot, hopping foot, and ruler foot and they all work great. I actually much prefer the hopping foot on both machines because I find the stitches to form more consistently. I bought a generic hopping foot for my 7700 after I used the convertible foot. Right now, I only use the convertible when I'm ruler quilting with the additional ruler foot attachment.
The generic ruler foot is a single solid piece foot that glides over the quilt sandwich if that's what you're looking for. It's thicker than a "regular" gliding foot because it needs to be thick to butt up against the ruler but it functions the same. On mine, you just change the height by loosening the presser foot screw and re-tightening it. It's still easy though maybe not quite as easy as the little dial on the convertible foot. It was also only about $12 though so that's a big difference in price
The gliding feet definitely have trouble if you set it too high (stitches won't form) or even if it's at just the right height for stitches to form, you may have trouble navigating over any thicker seam intersections. I do a lot of paper piecing lately so thick seam intersections is a thing for me.
Anyway.... all that to say that generic feet are totally fine especially for a cheaper machine! I prefer the consistent stitches I get with the hopping foot and I can see through/around it better, but a ruler/gliding foot does have its uses too.
eta: If you are marking your quilt with a Pounce, the gliding foot is likely better because the hopping action can bounce the powder off and you'll lose your lines. Had that happen even after setting the lines with hairspray.