Okay! Here's my 2 cents
If you have any length on your hair, meaning your hair is longer than jaw length, your hair strands are at least 2 years old, if not older. Thus, even if you have stopped using extensions since 2020, the possibility exists that the damage imparted by the hair extensions is still on your hair strands.
Everyone's hair has different sensitivities. Perhaps you may be someone who finds that using the clips, on already dry hair, exacerbates the fragility of your hair and makes your hair more prone to mid shaft splits.
Based upon the little I know about your hair history, and having not seen your hair, I think you are on track. My guess is that although you may have some mid shaft splits, the quantity and frequency of them are diminishing. You are seeing less and less. If that is correct, then as your new hair grows in and you cut away the ends of older hair, the newer strands will more likely not have mid shaft splits.
So, I would suggest you get rid of ALL clips, stop using them completely and find another way to pull up your hair. Continue to stay away from all extensions, especially synthetic hair because that can really break hair. Lastly, if you can avoid using the tangle teaser do so. But, if you use it, go slowly and gently with it and pay attention to the amount of pressure you apply. Listen to the sounds your hair makes when you use it and pay attention to how much you have to 'snatch' it through the hair and the amount of pressure you apply to 'snatch' it through. Snatching it through tangles is a tremendous amount of force. It destroys hair ends. I personally think it rips out hair ends but I've not had direct experience with tangle teasers so I don't really know.
Don't forget to document your hair findings in writing
and in
pictures. It is tedious to do, but so worth it. Good luck!