My bluetooth headphones do not have full volume.

I have a pair of Kinovio blue tooth headphones. I have used this brand for the last 5 years. It worked great with my android phones. However, with my Apple phones I cannot get full volume. I had an Iphone XR. I tried changing all the phone settings and even tried a factory reset and it did not fix the problem. I also tried resetting the headphones. I thought maybe it was an issue with the phone because it was refurbished

. I decided to just put up with it. It is now 3 years later and I bought a newer Iphone 13. I just switched phones today and I was very disappointed to find that it has exactly the same problem. I now realize that it might be a compatibility issue. Is there a way around this or is there another brand of headphones that costs $100 or less that will not have this problem. I don't understand why I cannot turn the volume up. If I am listening to a podcast and there is noise in the background I cannot hear. Also I like turning the volume to my music up when I am exercising. This is beyond absurd that I haven't found a resolution to this issue.