When they ban gender affirming care for under-18s, they mean ALL gender affirming care, including girls who need breast reductions and boys who need mastectomies due to gynecomastia. That's what gets banned. Any surgical intervention, trans or not, is made illegal.
And most gender affirming surgical care for the 13-18 demographic is being done on non-trans teenagers. I looked up stats for the Alberta specifically when researching and found out it was very close to less than 1% of surgeries were being done on trans teens.
The same is true for puberty blockers, most usage is for girls experiencing precocious puberty, and that becomes banned.
These blanket bans end up impacting a whole group of people who need access to this medical treatment for reasons that are not transition related.