I've recently been dealing with this as well, P000C slow cam response and P0018 camshaft-crankshaft correlation. I check data logs and could see as per the P000C code that the camshaft was in fact not tracking correctly. Swapped the position sensors and oil control valves separately to confirm that it was a problem with the sprocket. No change. Swapped the sprocket and the P000C went away. Data logs show that the camshaft is now tracking correctly but the P0018 code remains. Confirmed the learning tables in Techstream were still showing an out of tolerance value of 47.49deg, what it was before the swap. Tried a bunch of ideas to reset the value, reflashing, calid, etc, but no luck. I could see that the learned values had minor changes in the my exhaust cams after each try but the intake cams were held static. Decided to test the ECU in a friend's car, it has an ECUTEK license and I really didn't want to replace with everything going on this year. Lo and behold, it starts in his car (with a stock ROM) with no code and his learned cam values were within tolerance. He drove around with it for a couple days with no problems. It's now back in my car and it's also running fine for a couple days. Learned values are within spec. Might be worth trying rather than replacing an ECU if you have access to another BRZ/FR-S/86.
TL;DR
You replaced the sprocket and still have a P0016/P0017/P0018/P0019 code? Try swapping the ecu into someone else's car. Maybe it just needs to go into comms mode but I can't try that now.
Procedure to swap ECU:
https://www.ft86club.com/forums/showthread.php?t=102810