I think R&R Superslick / SRAM Butter / / Slick Honey are all rebadged Slikoleum i.e. the same stuff.
From memory the stuff CRC sold as “Brand X Dropper Grease” looked more like a thicker sort of white lithium grease.
In fact, the first time I serviced a Brand X dropper, the inside was full of whitish grease. After degreasing, I just used SRAM Butter and it worked fine for the three years I owned that post so I’ve always stuck with that.
Again, YMMV etc etc etc, this is not scientific, but across 3 posts (one up and brand x) if I use anything else the post gets gummed up.
I have to regrease the collar seal / bushing every couple of weeks on my One Up post or it gets sticky. Apparently a known issue with them.