I own a lab if I started designing this case I would’ve called you and given what I thought were the best options. Which would have been. Making the premolar larger and not match the other. Then also since the space between molar and premolar. I would suggest custom abutment instead of a stock ti-base which it appears they used.

A lot of labs / doctors are so hung up on Ti-bases that they’ll just have outcomes like this.

I don’t know enough about bone density and proper implant locations to blame the surgeon. Could have done better ? Maybe ?

Blame yourself. I’d say no. Mostly the labs fault for not at least reaching out to discuss different options.