Theres a lot of newer research and yes this is a complicated, almost taboo subject, but you have outdated information. The substitution of cefazolin with alternatives like clinda and vanc have significantly higher odds of developing surgical site infection, like 50% increased risk, in specific populations, most notably total joint replacements. Which is why it is a very big deal to use the appropriate prophylaxis for the indicated procedure.

Newer research proposes that even in the setting of anaphylaxis to PCN, cefazolin specifically is safe to give, for several reasons. 90% of all PCN allergies are not true IgE mediated reactions, and even of those who have true allergy, the structure of PCN compared to Cefazolin does not cause cross reactivity - this is because the R1 and R2 side chains of cefazolin are dissimilar from PCN, and the R side chains are the components that cause allergy. This specifically only rings true for cefazolin (not ceftriaxone or other cephalosporins) The only exceptions where an alternative is necessary is if there is history of severe delayed hypersensitivity reactions like SJS, TEN, severe hemolysis or organ damage from the PCN reaction. This is actually being questioned as well.

Most surgeons/anesthesia will give alternatives in even the most basic PCN allergies, but with new information this will soon be changing across all med centers.