Looking back, now that you've straightened out your main relief, it's time to check all functions against specs. Additionally, check functions with a temp gun. So when you curl your bucket in/out , shoot surface temp, hold over relief for 10 seconds or less. See if the barrel or hoses heat up. Heat indicates bypass. Perform the same test on arm and boom, obviously you can only do boom up without digging a big hole. You definitely have one or more piston packing degrading based on what the return filter looked like. If you have a storage drum, I would advise draining the tank so you can pull and inspect the sump strainer. The last thing you want is to starve your pumps of oil.
Really glad to read it was a simple fix.