For now, in the area of heavy airlift, China cannot help but play catch up. The technology has been matured by others, notably the US and Soviets/Russia. All that fanciful 'stealth' versions are speculative, even for US as we have other priorities.
For strategic air transport, China does not have anything that can move -- within the crucial 48/72 hrs window -- the US 82nd Airborne equivalent to anywhere on mainland China, and by that I mean not only troops but all of their support including armor. Not only does the PLA do not have a capable strategic heavy lifter, the PLAAF does not have sufficient quantity of whatever is capable anyway. About 30 IL-76MDs? While the US have over 200 C17s, not counting the C-141 and the C-5, the last is freed and used for outsized cargo. Supposedly, the PLA's 99A2 main battle tank cannot be air transported with the current airlift capability. Not only that, because the C-17 came from matured platforms like the -130, -141, and the -5, all with proven global record, from tactical small units to their battlefields to strategic division level transport, the C-17 was given tacit trust by potential customers even before the first delivery.
The Y-20 is about two years behind schedule, which is not to sneer at because the US have our own manufacturing issues, but when coupled with an engine that for now lends the perception that said engine is crippling the Y-20's optimistic capabilities, it will be several more years, possibly a decade, before the Y-20 is truly capable for mass production and the PLA can be rightfully admitted to an exclusive club of heavy strategic airlift capable militaries.