No. Soco never takes any of your creator commission. TikTok pays you the full creator rate as usual, plus the extra rate you get through a TAP link. Soco earns from the brand's side of those deals, not from your payout.
Where Soco's money comes from
Soco earns in two places, neither of them your commission:
Paid subscriptions: what you pay for Soco Pro.
Brand-side TAP increases: brands give Soco an extra commission percentage for sending creators to their products.
When the higher rate reaches you
When you upgrade a link, the higher commission applies to sales from videos you post after applying the Soco link to your showcase.
Next steps
Your next question is probably one of these: