Altitude is definitely a challenge, but I don't agree that peaks below 4000 m are amateur mountaineering and elite is reserved for 8000ers. As an example, Marc-André Leclerc made some incredible first solo ascents below 4000 m like the Corkscrew on Cerro Torre, at 3128 m (10,262 ft). The Alpinist [1] is worth watching if you are into mountaineering!
1: https://m.imdb.com/title/tt11790780/