The phone clip + is niot the problem, as no streamer, regardless of manufacturer/maker, will have any quality sound with open fit as much of the of output from the steramer will exit the ear canal rather than to the eardrums. So, if you can only live with open fit HAs and quality of fidelity is important to you, then don’t bother getting any streamer, regardless of brand.
I agree the Phone clip+ microphone isn’t the greatest, I don’t think it is much worse than other HA streamers. The challenge of using more powerful micrphones is that they would more quickly drain the batteries, resulting shorter charge. As newer batteries life keeps improving, as they are in smartphones, then the streamers microphone will likely improve also.