Hello Dark Espeon, thank you for providing another list structure.
Personally, I think the supporter count is just fine, but I can see the concern.
Tate & Liza - I really don't like this supporter at the moment. I might warm up to it in the future, but I've stated my reasons for not being fond of it in the 2019 supporter cards thread. It's a supporter that combines the effects of a supporter and an item card, and the fact that one of the effects is something you can find on an item devalues it for me. Particularly due to the fact that this deck runs energy out of the discard pile, I think that Sophocoles is a far superior than Tate & Liza in this deck if we wanted to extend our draw support.
Copycat - I think only one copy is necessary for the time being. I see Copycat as a card that you play after your opponent plays Steven's Decision and you want the ability to respond immediately by playing something like Copycat that allows you to draw your cards and use them too. Something that I think should be taken into consideration is now that everyone expects a few copies of Judge & Copycat in everyone's deck, I think everyone should/will adopt a playstyle of making sure to always end turns with 5 or less cards in hand to prevent their opponents from having a reason to use those supporters in the first place. But having 1 copy to respond to Steven is still a good idea in my eyes.
Lillie - I'm not sure I like the 2nd copy. I think that 1 Steven, 1 Lillie, and 1 Copycat are the "holy trinity of opening supporters" come post rotation.
Turn 1 going first: All 3 supporters have conditions in which they would be useful here. You can Steven after setting up a decent bench, or Lillie expecting to draw more cards to set up immediately. At the same time, if you mulliganed a lot and your opponent is sitting on 8+ cards, you can go ahead and copycat that.
Turn 1 going second: Lillie and Copycat are especially good here as you sometimes want to make sure you have your attack for turn available, especially if you're using something like Alolan Vulpix. Steven still isn't a bad idea, but since you're going second, it gives your opponent the chance to Judge you or profit even further off of you on their 2nd turn.
I'd say you have enough turn 1 options between the three supporters, so you'll be fine most of the time in terms of not having them all be prized. I also don't think Lillie has much value outside of turn 1. Sophocles grants you a hard +2 to hand size regardless of your hand, but he also discards 2 cards to prevent them from going back into your deck after a Judge or your own Cynthia later in the game. Lillie can net you an overall +2 to hand size if you play her at 4 cards in hand, but she can't sculpt your deck without the ability to discard cards.
Long story short, I would make my supporter line up look like this if 10 seems a bit too skinny:
Cynthia x4
Guzma x3
Sophocles x2
Copycat x1
Steven x1
Lillie x1
And that gives us 12 supporters, 6 of which being very stable draw supporters for the deck.
Energy Loto is an interesting choice and I can see why you put it here. I'm just not certain the deck actually needs it to function. Unit Energy is also an interesting choice, but since I think Beast Ring is better energy acceleration than Energy Loto, I need to be running basic Metals in order for that to work. The reason why I think Energy Loto shouldn't be necessary is because of the interaction of Sophocoles vs Lillie that I just mentioned. Early on in the game, you will be seeing yourself playing a lot of Ultra Ball and Mysterious Treasure to find the Pokemon that you need. Because of that, you will be discarding either a bunch of energy, cards you don't think you'll need again, or both. By discarding your hand a lot and searching out cards directly from your deck, you make it easier and easier to naturally draw the energy you need since you will be filtering your hand and deck. If you playout your hand like this and then play Cynthia, odds are you're going to see energy. This deck has a cute energy balancing act going on where you always want to have an energy in hand to attach per turn, but you always want 2-3 psychic in discard at all times to enable Malamar, and at the same time you want energy in deck to use Beast Ring. Overall I don't think Energy Loto is needed and Beast Ring should take much higher priority for revenge kills when your opponent snags the first GX kill on you.
Also, I think 3 Ultra Necrozma GX is the right number. We need all the consistency we can get. That being said, I'm not against only 1 copy of Dawn Wings. I've been questioning how much I care about 2x Dawn Wings when we can just spam Altar of the Moone.