my ex MIL always used wondra for gravy and it was always smooth. I use cornstarch like my mom,
and it tends to get gel-like when cold, but will warm up nicely the next day if a bit of broth is added while warming and there are generally no lumps.
Yes, very often-took a cooking course where the chef insisted
that wondra was a wonder because if you used it you would not hacw lumpy grave AND she said that you could cook the gravy only two minutes after incorporating the flour rather than the 20 minutes usual to get rid of what she called the "raw" taste.