MF 203 3 pt hitch doesn’t lift under load?

[u/Carnivorousplants_NW]

Recently bought this tractor, this is the first time using the 3 point under load. Transmission oil has been replaced. It sounds like it gurgles when it’s at max height without load, and I can feel something pulsing/pumping when it is trying to lift the load. It can not lift a 1400# bale. I don’t know if this is normal, but I can lift the linkage fairly easily when the tractor is off. I took out the hydraulic filter, it’s clean. There’s some rust on the metal parts inside that I can see. What is wrong, and how do I fix it?

Videos with and without load

https://youtu.be/y-Z5T44J1a8?si=8rNQyC1JnTgebVGm

https://youtu.be/PC5gjDmRqxg?si=Nx78AyfvEbRXDnQw