Most people are confused by the phrases "hardware encoding" and "software encoding" in the Export dialog summary section.
Those have nothing whatever to do with your GPU, or Premiere's use of it in the export. Period.
The only thing that refers to is whether or not you have na Intel CPU with the Intel QuickSync internal hardware, and the use of it is enabled in the BIOS. As you're running an AMD CPU, well ... that comment refers to an Intel-only "thing". I wouldn't worry about it anyway ... from testing, it may be a bit faster on Intel CPUs that have it ... but the 'software encoding' will probably do a slightly better job of the encode.
You set the GPU use in your Project settings dialog when you set Mercury Acceleration. For Nvidia GPUs, that would be CUDA of course. Premiere will then use the GPU for what it uses a GPU for ... and when it gets to something that uses one of those effects. It does not use the GPU for basic encoding.
Primarily ... think major frame resizing, Warp stabilizer, color such as Lumetri. Go to the Effects panel. See the lego blocks at the top?

The first one indicates whether an effect is GPU accelerated ... the second, whether it's processed in 32-bit float or not, and for any resizing/color you want 32-bit float. Never use a color effect that isn't 32-bit float ... to be safe.
And realize, for basic encoding ... there won't be much if any GPU use going on period.
Neil
EDIT: This used to be the case, but now you can actually use your GPUs to assist exports for any GPU. For those with Intel Quick Sync, hardware exporting is usually faster with GPU export, however, Premiere Pro will pick the faster of the two automatically.