Biome Generation in the Nether and End? (No, but with okay workaround)

(Edit:For anyone looking for an answer, it's no)

(Edit:But, I added a okay workaround and extra stuff for fun)

(Asking about this in the latest snapshot version)

Is biome generation possible in the nether and end yet? If so, can someone instruct me on how to add biomes to these existing dimensions?

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Workaround to "biome" generation to existing dimensions

(It's alright, but, still doesn't work the best, and it doesn't actually set a custom biome. This be better if you want to make mini mini biomes that are more of an addition to existing ones, unless you are really good at making things work)

(Also, If your wondering why this is so long, I tried to make this as beginner friendly as possible. Also, I put most names of things in "")

(Also, this may be a mess)

-First, we take our biome's grass block (Which sadly has to be different from other biomes in that dimension to work properly)

 -In the Generation settings, and choose the dimension you want your biome to be in, Then depending on which dimension you choose, make the grass generate either in the             "end_barrens" or "nether" as those are mostly blank, and wide biomes, but, you can choose any other biomes you want. ("small_end_islands" or "soul_sand_valley" may also work well)

-Still in the generation settings after you decided the biome, pick to replace that biomes most common ground block. ex, Netherrack for nether, Soul sand for the Soul Sand Valley, or End Stone for the End Barrens. Following that, set the "average amount of ore groups per chunk" to either 1 (Rare) up to 31 (Rather Common), however, the higher might lag the  game. The "Average amount of ores in a group" should be over 13, but under 32. (Unless the grass of your biome spreads, it'll unfortunately be quite small and scattered as we are    depending on the ore generator, which is somewhat limited when it comes to this. (I'll update this entirely when I come back to Minecraft Modding))

-After setting your desired generation heights, still in the Generation tab, we want to make a Additional Generation Condition, click the green plus button. We want to make a procedure to check if the block above is air. So first, we want to grab a template procedure from "Procedure Templates" called "Check type of a block below". After that, we want to change [y - 1] to [y + 1], and set the empty box to "Air" (It should be the first block after your mod's blocks.)

-Following that, still working on our procedure, go to "Logic", and grab the "true" procedure block, then go to "Flow control" and grab the light blue "Return" procedure block. attach the "true" procedure block to the "Return" procedure block, and place them into the "do" part of the "If" procedure block we made earlier. And before we are done with the condition procedure, we want to copy the "Return true" we made, and place it below on the end of our condition procedure, then change the "true" to "false".

Now, you should have the biome generating (In small patches), but, we are not done yet.

Custom "biome" "tree" generation

(Tree is in quotes because it can be whatever you want (Like houses, mushrooms, or floating stones, whatever you want really), also, this part is a little less beginner friendly as this has already taken me an hour to write and check)

(Also, this works with actual custom biomes)

Making the "tree"

-First, we run minecraft from MCreator, and create a flat world in creative mode with cheats enabled. After, give yourself 1 minecraft:structure_block and 1 minecraft:structure_void if your "tree" has blocks that should remain air (Void blocks are blocks that can be filled with other blocks while air (only if your including void blocks in your structure) will remain air even when the structure is placed. place a structure block, right click it and click "Data" so it says "Save", then, set the dimensions of the "tree" (Up to 32x32 I believe) then build whatever you want inside the borders provided. 

-After you are done, go back to your structure block, name your structure, then click "SAVE" (The one in all caps). Then exit the game. (You can make multiple structures at once without closing and opening the game again)

Adding the structure

-Back to MCreator's workspace, we want to go to our resources, then go to "structures", then import a structure from minecraft, select and add your new structure, then head back to "mod elements".

-Now, we want to make a "Structure spawn", select your new structure, then the rest is up to you (Note: blocks to ignore when placing: select "air" if you haven't added void blocks, or "structure" if you have, and you want you have empty spots on your structure. The "restrict to block types" should be your biome's grass block, and make sure the biome and dimensions which your structure spawns in is the same as the biome's grass's)

And now, I leave the rest to you. I hoped this helped at least a bit. I'm tired

(Last Edit: I truly suggest instead of using this, you make a clone of the dimension you want to add biomes to. Add a procedure to check if the player is in dimension (Or biome for the end unless you want to remove the ender dragon fight, or can or want to replace it.) and teleport them there, portals also might need  to be slightly different and it may take awhile, but, I can assure you, It'll probably turn out nicer then what you'll get out of this)