Hydraulics are all alike. Transmissions, brakes, power steer, or shocks.. They leak when they're wore out. It's rarely just a seal issue.
Replacing the seal may slow or stop the leak for a bit, but it's usually not a permanent fix. There are exceptions, but unless it was near new before being exposed to something that killed the seals, chances are it's just worn.
Best to dig in and do a proper rebuild and tighten up whatever is worn and causing the seal to be impinged on, causing the leak.
No reason not to try it yourself, but you're likely to run into some challenges with certain operations. I'd search out a manual and probably a few videos beforehand and decide if it's worth it or if it would be better to buy a quality reman unit.
