I got new trim rams as my old ones were leaking; installed them, bled them according to the manual, twice, but they aren't working. Trim works going up/out, but instantly starts sagging downwards. Also, they don't pull the lower unit down at all. Pressing the "down" button = no difference. Alpha drive.

Did it stay up with the old cylinders? If so are you sure you reconnected all the lines correctly?

Yep, but they leaked fluid/water so the system would turn into grey goo.

Sounds like you have a internal leak on the rams? Or could be rams that have frozen in place.

Are you saying they leaked and made grey goo BEFORE you installed new rams? Did you replace the pump or clean it out super well? How about the hoses? The valve body could be damaged if the water was in there for almost any length of time. The screens in the pumps clog easily. You don't say if you heard the pump running both directions, but the sagging leads me to believe there may be valve body damage assuming there are no external leaks.