Don't have any product recs for you, but when I straighten I just use a leave-in (same one I use when I wear my hair curly) and some jojoba oil. I apply the jojoba oil after blowdrying and before ironing, then again after ironing. It leaves my hair really soft and it doesn't feel gunky if I let it go several days before wetting/washing again.
Faith, 3Aish redhead
Mama to two wild superheroes and a curly-headed baby boy