If you think money is what is on the table here you lack imagination. It's the "Trump knob" in TikTok's ranking algorithm that is the real thing of value here.
No actual deal is necessary here. It's obvious to everyone involved what the deal is: TikTok ensures that its content is friendly to Trump, TikTok stays unbanned.
Despite both ending up with TikTok staying up in the US, having the ban be unconstitutional or not exist at all is different from having the ban in place and a deal to avoid it. What the ACLU was fighting for would have removed leverage from the government/president.
Technically, and unfortunately, yes. They are a single-issue organization, and that single issue takes precedence over any other consideration. I doubt many of them who are involved are happy about him being able to use this to consolidate, but there are always external effects when you have a single major priority (especially if it's a good one).
No actual deal is necessary here. It's obvious to everyone involved what the deal is: TikTok ensures that its content is friendly to Trump, TikTok stays unbanned.