I checked out Patreon and SubscribeStar and they only offer it at a discount to T2 supporters and not at full price. The only place they list it at full price is on Itch. Thanks for your help anyway.
Viewing post in Senia (World's Crossing Academy - Extra Romance Route) comments
Read my Discord messages again. I told you I'd give you the DLC in Discord DMs if you signed up on T2 once, since that's the same price as Senia. Meaning I would send you the direct download link directly in Discord DMs, not that you would follow the Download links on SubscribeStar.
I also told you that T3 gets all DLCs for free. Senia ($5), the Fantasies Collection ($10), both Pandora's Box packs ($5 each), and all of the pinup packs, all for $10. You can sign up for it once, download all of it, and then cancel so you don't get billed a second time, if you want.