Indeed, the stars are out of focus and elongated. The super takumar does not come to focus in Ha due to the infinity stop of the focus ring. I removed the ring and pushed the end bumper a bit further so that I have good focus for Ha now. No special tools required, just a small screwdriver. In this video you can see how to get access to it:
It works well now for Ha but it has some serious longitudinal CA without filter. Some effort in post processing can mostly fix it.
The elongated star problem can hardly be solved on a tracker. Only little deviation in polar alignment will cause drift. For the DSLR you use I'd rather try ISO800. You have a very limited dynamic range at high iso and your image has no star color. All stars are blown out. At lower ISO it will be better.
For the equipment that you have it is a good shot but you probably reached the limit now. If you want to go deeper in it, resist the temptation to get the infamous AVX, go for a sturdy mount in the 1.5k$ range. I use the takumar on my EQ6-R as well as telescopes. Here you can compare your image to my version of the California Nebula, also taken with Canon DSLRs and Ha-RGB combination as you do. I call it Ha-OSC, though.
There are plenty of imperfections in this image as well, but you can probably see the difference in star shape and size. This is what mxpwr is pointing out.