Ahhhhhh, now that you mention it like that, I feel less sure about the flyback. However, lowering brightness also makes bad convergence less obvious. You'd want to see some proper test image patterns to be certain. Like at least a white crosshatch pattern to see how your RGB is coming together.
For the Flyback, I guess K7000 flybacks are probably still easily available and not too expensive to swap-out. Not a bad thing to have on hand as a spare too.
If you have a rings tester, also called a Line Out Put Transformer (LOPT) or simply "flyback tester", you can check to see if there are any shorts etc compromising the coils inside your flyback. No need to remove flyback from PCB either. What it does is pumps a short pulse of very low-amp current into the coils which produces a kind of echo, or ringing, in good coils. The meter detects this "ringing" and lights up a row of LEDs. If most or all of the LEDs light up, flyback is good. If none or only a couple of LEDs light up, flyback is probably bad. I have the original Dick Smith flyback tester, Anatek also sell one based on the same design. It is also good for testing other things with lots of coils like transformers and vertical deflection yoke.
If you are interested in getting one of these, I have a few of the original Dick Smith kit versions of both the flyback/rings tester and the ESR meter I mentioned earlier, still in original shrink wrap! PM me if interested. Just a little bit of soldering required. They are very useful for CRT repair and electronic repairs in general.