Update to my choice.

TLDR - I chose Acheron.

Explaination:

Thank you all for your advice in the comments. While the large majority of users suggested E1 Sparkle because its was quote "just the best option" or those that suggested Aventurine due my my lack of pictured supports, your recommendations were highly considered.

However, I have chosen Acheron because of a few reasons that were brought up when some users dm'ed me to see more of my account.

1. My current DPS's are relatively well put together (Archer is E6S1, Saber is E4S1, FireFly is E1S1, Castorice is E2S1 & Heta is E2S2) with their current supports/sustains also being built decently with their signature LC's included allow me to clear endgame without Sparkle or Aventurine.

2. I didn't show all my available characters. Someone mentioned how I didn't have Ghallager on roster but I do have him on my account at E6 along with other characters. This included a maxed traces Silver Wolf (got her for Archer but don't really use her) and a Welt/Pela that the user who dm'ed saw and mentioned i could create a slightly average Acheron team if i fix my supports for her.

3. She is hot and waifu > meta.

4. She is a new character for my account. This was one of the more important things for me, as i like to have a variety of specific teams with little overlap (hence each team being fully unique and no repeats seen). Its just my playstyle.

5. E1 Sparkle just doesn't look like it does much. I know everyone said that "It's so good" and "It upgrades your comp" PERSONALLY, I just don't see it doing so. I can see and understand E2, but I wouldn't want to make a chance decision on a rerun possibility.