When I first got my 4Runner I installed an aftermarket loaded head, as the oem head had warped beyond repair. The new cam quickly developed horrible wear at 3-4 lobes.
I researched my issue and quickly found dozens of similar complaints, so simply getting another loaded head wasn’t an option. While I had junked my original head, I had removed all the oem springs and valves and stored away. I got those out and dismantled the head that was on my engine. The camshaft wasn’t discolored anywhere, so oil starvation wasn’t an issue. I compared the valve springs and could tell the aftermarket springs were much stiffer than my oem ones. I also saw the aftermarket valves had a lip significantly thicker than the oem. As was the washer plate that the spring sat on.
I theorized that the thicker washer plate and valve decreased the space where the valve spring got compressed into, exacerbating the issue of the stiff spring. In fairness, I have no data beyond observation to validate my suspicions.
I got a used oem camshaft from a yard, then reassembled the head using my old oem valves, springs, washers, and keepers. Lapped in the valves myself. No issues since. I must have pulled the valve cover half dozen times the first 100 miles to inspect the cam. It's possible that simply using the oem cam would have resolved the issues, but I scrutinized the valves and springs as others had speculated the same in my research. I also didn't want to pull the head a third time if avoidable.

Do you still have your old head? If not, you could source a 22RE head and swap everything over like I did. I’m willing to bet your issues will go away. Can you post a photo of the cam wear on the lobes? The rocker surfaces didn't get beat up?
As far as where some of the 22RE vendors get their components i don't know. that would go a long way in determining quality. On one of my future trips to the PYP yard I plan to get a 22RE head if I can find one that hasn't been machined too much.