I use the last HD model (2015's A8,1080p) because when I updated to 2017 ATV-4K, it could not play my largest HEVC files properly. I even replaced that unit and had the same issues. Went back to the ATV-HD which works mostly fine if I let it buffer a bit. We're two 4K generations deep now (A12 & A15 Bionic), and I'm certain the newer A17 Pro hardware will be more than fast enough to stream my BR-Rips via Infuse. I'm not interested in getting what will soon be the longest running model ever, when it's about to be made obsolete - as you can tell I prefer longevity.
I planned on updating in 2023 (based on the average release cycle), and it's been painful waiting for these delays since then. Now the AI-fueled SSD/RAM shortages risk hurting the price or specs. It's been a tough go waiting for this thing.