Good news! In the last year things have gotten a lot better!
Snapdragon 835, Android / Chrome circa June 2017
Snapdragon 845, Android / Chrome circa June 2018
Note this is Speedometer 1.0 to keep the comparison apples to apples. Between the respectable hardware bump (finally) and major Chrome/Android JS improvements, we’re looking at 2x improvement. Vastly overdue… but I’ll take it!
This is finally iPhone 6s territory which I’d call certainly fast enough for native Discourse performance.