You don’t have a lot of options for a non-GT. GT lowering springs will work, but the gap will be pretty big in the back. I wouldn’t recommend it. If you can swing for coilovers, Godspeed and Rev9 both make some (low end Godspeed: Godspeed MonoSS Coilovers Kia Forte Sedan [Torsion Beam] (2019-2020) MSS0183
High end Godspeed: Godspeed MonoRS Coilovers Kia Forte Sedan w/ Rear Torsion Beam (19-20) MRS1421
) Haven’t read about peoples experience with either Godspeed option, but people seem to like the Rev9 option for the money. This also allows you to dial ride comfort and height to your preferences.
For lowering springs, you basically only have one option. People have recommended either M&S Storm lowering springs (K5 Optima Store has them - Storm Lowering Springs
as well as on M&S’ own website K3 FORTE (BD) LOWERING SPRINGS — M&S America
) or Eibach lowering springs for the AD chassis (2017-19 I think) non-turbo Hyundai Elantra, which is basically the same car. Can’t find a US link to those though, and I also haven’t been able to find anyone who has experience with either option. I’ve been running into the same problem, since I want to lower my ‘21 FE manual. Might just have to bite the bullet on one set and go for it.