Oh no, oldtisme! The moment you went from walking foot to Supreme Slider I was biting my nails for you! Those crazy things are
not cheap, so I really feel for you.
Hang in there with the FMQ! You'll get there. I found that by switching to 50wt Aurifil thread that matches my quilt top, you can barely even see my stitches. Or you could do 100wt YLI silk thread in a matching or analogous color & it would be practically invisible.