Well, the AE isn't gone -- you can still use it on clothing and on any CC1/2 avatars. The only thing that's missing is they haven't gotten the 4K Substance texture done for the CC3 avatar skin. The AE works on substances only (so theoretically you could assign a substance to the CC3 character and then be able to use the editor for it).
What I show is just bringing in a Daz texture and applying it to a CC3 avatar but, again, you can do the same thing with a CC1/2 texture. So let's assume a workflow could look like this -- you are deadset on using the AE to generate "old age" (IOW, you don't want to use a texture like I brought in from Daz but rather one that is supplied with the CC1/2 avatars). You load in one of them, use the AE to get the texture looking the way you want, and then convert the avatar to a CC3 one. Presto -- you have a CC3 character with the old age texture (which you could save out and use on any other character you want).
And the texture I used isn't even done at 4K -- so you can get even more detailed if you like (I don't want 4K textures on my avatars for animation purposes). So there are all kinds of workarounds.
They have announced they WILL have the 4K Substance avatar texture available in the 3.1 update, but they don't know when that will be released. In the meantime, you have plenty of options to get the look you want.
Alienware Aurora R12, Win 10, i9-119000KF, 3.5GHz CPU, 128GB RAM, RTX 3090 (24GB), Samsung 960 Pro 4TB M-2 SSD, TB+ Disk space
Mike "ex-genius" Kelley