Yosemite in late August has typically great conditions: The bugs have disappeared, especially in a low snow year like 2021, the weather is still good, and you only get the occasional mid-afternoon summer storms. Typically, water is still available in most streams, although seasonal ones can be dry. This means that in general, you can pick your typical three season load and be fine.
One caveat is obviously that bear canisters are required in all of Yosemite - Ursacks are not allowed. I had tried out the Nunatak Bears Ears last year on a shorter trip, and really enjoyed the integrated system for canisters. My initial impressions were confirmed, it’s a fantastic pack and I loved it. The bear canister also was useful to take the brunt of the abrasion when scrambling.
Another new piece of gear were the Locus Gear CP3 poles. I had also tried out the Gossamer Gear LT5 at home, but thought they were too flimsy for off-trail. The CP3 poles on the other hand were a great compromise between weight and stability. I had to adjust the tension a little bit to stop the poles from collapsing, but that’s no big deal.
I started the south loop with the Borah Gear vest, but switched to the Cumulus Primelite for the north loop. It was probably a little overkill, but better safe than sorry. Some of the nights did get quite cold at the end, and I’m generally a very cold person.
For shelter, I was excited to try out the Zpacks Hexamid, which I had recently acquired from a user on Reddit. Unfortunately, I did not particularly like it: It was just a little too small for me, and too fiddly to set up. After the south loop, I switched to my Gossamer Gear Twinn tarp, and did not regret it. It allowed me to cowboy camp when possible, and protected me from the winds in the canyon just fine. The Hexamid is a fine tent, but I prefer a tarp in mild conditions, and a more storm-worthy tent in windier conditions.