Good on you for what attempted already. I looked at the print and it appears there is a worm gear (item 50) and a driven pump (item 61) behind the clutch. I suspect one of the 2 has failed. I know you have done most of this already But does it ooze with the bar off?
Oil System Plugged:

1. Remove the clutch cover, bar, and chain, clean the bar groove, any holes and passages on the rear of the bar (both sides, consider rotating the bar), if equipped with a sprocket nose ensure it rotates easily at least one complete revolution. Clean the saw oiler hole and channel. Insert a blunted, hooked piece of wire through the oil filler hole and pull the hose in the oil tank out. Pay attention to the screen or filter on the free end (clean or replace, difficult to determine serviceability). Start the saw and see if it oils when revved up (oozes down side of saw). If yes reassemble your saw. If no, continue with 2.
2. Work your way through the linkage (use IPL to identify components and locations) cleaning and replacing any defective parts as you go. Carefully check the hoses for cracks especially at bends and connections. If equipped with an oil pump it is usually behind the clutch (clutch is a left handed thread). Please make extensive notes & some digital pictures will help during reassembly.