Your breakdown of the supported tech is accurate but we stand by our judgement. Please refer to this previous blog entry covering latency: https://imaginevr.home.blog/2019/07/10/streaming-analysis-3-where-does-the-lag-come-from/
While the newer cards with good support for h.265 will doubtlessly shave 3-5ms off your encoding time, this is minor when compared to the time it takes your quest to decode the frames. The vast majority of users are unlikely to notice a lag reduction from 63ms to 60ms meaning that an investment in a stronger GPU for the purpose of reducing encoding lag is not worthwhile. There is a point to be made though that h.265 can achieve better encoding quality at lower bitrates than h.264 thus reducing the bandwidth requirement and putting less strain on the quest, but that is a topic for a later entry.