A big thanks to u/lpgainey, who posted a video of this fix a few years ago and I just wanted to post my experience with it and give it a bump. This seems to be a really common issue with the G3 and I want more people to see it and not despair like I did.

I struggled with finding these parts in-store, so I'd buy them online. I bought them from amazon, here are the links:
https://www.amazon.com/dp/B015A325WM?psc=1&ref=ppx_yo2ov_dt_b_product_details
https://www.amazon.com/dp/B07FRLRWD4?psc=1&ref=ppx_yo2ov_dt_b_product_details
https://www.amazon.com/dp/B01LAH7UBI?psc=1&ref=ppx_yo2ov_dt_b_product_details
All of these materials cost about $25, which gives you about 50 of each. This already covers the cost of one set of 5 replacement screws from backfire, highly worth it in my opinion.

Some difficulties I had: The washers I bought are a bit too wide. When tightening the nuts, it bends the washer against the curved back part of the wheel frame. This is fine since it protects the metal of the wheel from the washer, I just hope I'm not bending the ends of the bolts. Everything seems secure so far. As I said in the photo comments, I highly recommend using a proper socket wrench when tightening down the nuts, as I used a serrated plier and it tore up the nuts pretty bad. If anyone has any questions, let me know! Again, credit to u/lplainey!