With 2 brands and 8 platforms, I would separate the problem into workflow first and tool second. Make a quick list of what is actually painful: scheduling, resizing media, approvals, analytics, asset storage, or keeping the two brand voices separate. A lot of tools look similar until you test those exact pieces.
For cross-posting, the big thing I would check is whether the platform preserves quality and lets you customize the caption/creative per network before publishing. True one-click posting sounds nice, but it can make everything feel slightly off. I would run a one-week trial with 10 real posts, not demo content, then compare media quality, failed posts, notification handling, and how long it takes to fix a mistake. That will tell you more than reviews.