You might want to check out this website: https://glutenfreeonashoestring.com/. The author has lots of recipes (including more than one recipe for blondies) and advice on both commercially made and DIY gluten-free flours. Which GF flour you use matters and different flours are best for different types of baked goods. I've made her GF flaky pie crust a few times and it turns out great.
If you are going to convert the recipe above, you'll most likely want to add xantham gum, increase the moisture content slightly, and possibly increase the leavening agents (baking powder and baking soda).
Many GF recipes include xantham gum, either in the flour itself or as an additional ingredient if your flour doesn't include it. Xantham gum provides elasticity and stickiness.
According to https://www.tasteofhome.com/article/converting-recipes-to-gluten-free/ (and based on your comment about a previous recipe you tried to convert), you should also increase the moisture content, either by adding an egg, full fat milk, or buttermilk, or substituting some of the liquid in the recipe with sour cream or mayonnaise. This site also has some good advice on converting recipes to GF: https://theheritagecook.com/converting-recipe-gluten-free/.
For this recipe, there isn't much moisture besides the eggs and peanut butter, so you wouldn't replace any of that with something else. I would add something — maybe 1/4 cup or less of applesauce or apple butter. The flavor would be mild and compatible with the other flavors. Or you could use dark brown sugar (instead of light brown), which will have more moisture content. Another option might be to add a tablespoon of molasses.
The last site also suggests increasing the leavening a little. I'm not sure if you'd need to do this with this recipe, though, unless you prefer your blondies to be more cakey than fudgey. Given that there is peanut butter in the recipe already, I'm guessing this is a fudgey blondie. I've never tried to make a change to the leavening in a recipe, so I have no advice on how much you would add.