That's one of those questions like "how long is a piece of string?" but this is what I've seen over the past 3 months:
Release date patterns have only recently started to be more or less reliable now that governments are indicating they will open up to international travel. That's particularly so for Australia where most airlines stopped flying here and stopped listing any flights at all.
Individual airlines have varying J release patterns for differnt routes. You really do have to look at each route on its own merits
JL - 4 - 6 weeks ago there was excellent availability for some routes such as HND - SYD right on 360 days but for LHR - HND I didn't see anything around 360 days at all, but then sporadic availability started showing up at about 330 days. JL HEL - HND was only showing Y, as well.
QR - Routes into and out of Australia have only recently even started to be listed for revenue fares. J awards have been exceptionally variable from one route to another. E.g., there's been plenty of J available for JNB - DOH at 330 - 360 days but virtually nothing showing on flights to connect to from DOH to Europe such as CPH, NCE, ARN, OSL etc. over the same time frame. I did see some European routes available at 250 - 280 days. That made trying to book connecting flights almost impossible.
Part of the reason for that might be because JNB-DOH has 3 flights on most days but some of the flights connecting to Europe have only one flight a day.
AA. I haven't searched for AA availability in recent times but they are notorious for not releasing J awards at around 330 days as expected. For some routes they may not release any seats until approx. 250 days out and for others like LAX - LAS they may never release any J at all. Another bugbear of AA is that they very often only show J availability between 2 cities via some other out-of-the-way city with very long transit times or which blows out the overall trip distance so much that the total trip time is long.