If I recall correctly, sometime ago, one of the big shrimps (either on Weibo or Twitter) retorted against a comment to a post that the US is ahead of China in ACE/VCE development for the 6th-gens with the "The US hasn't even started high-altitude engine test bench trials with their VCE/ACE meant for the F-47" reply (or something of similar effect).
And recall that we've seen those
VCE/ACE slides by CAS from November last year (where high-altitude test bench trials have already been completed, and their VCE/ACE isn't even meant for the J-36 and the J-XDS/50) - I think China's VCE/ACE development progress is getting somewhere encouraging (at the same pace as the VCE/ACE from CAS, at least).