In the first Patch 10.2 PTR build, the item levels of Dragonflight Season 3 have been revealed and Crafted Gear has taken a massive nerf.
Edit #1 (10:25 AM PDT): Blizzard has reached out to Wowhead to comment that the item levels for Crafted gear are outdated and they provided updated item levels for Crafted Item Levels in Season 3. The article has been updated.
The important thing to point out is that the item level increase on the PTR right now is 39 item levels, but normally this increase is only 26 item levels. This means that players will be more undergeared coming into Dragonflight Season 3 than normal.
In Dragonflight Season 3, a Mythic Aberrus geared player will have gear equivalent to LFR of the Dream raid (typically Mythic previous raid is equivalent to Normal of the new raid).
Blizzard has provided the item levels of the Season 3 crafted gear:
You can see that the new Aspects crafted crest caps at 483 item level. What does this equate to in Season 3?
The max rank of crafted gear from Aspects is equivalent to doing the new +20 keystone and is equal to early-mid Mythic raid.
Only a slight nerf to crafted gear.