The AP exam is not a requirement so no disadvantage of not taking the exam other than not getting college credit for the FL.
The UC’s want to see 2 years minimum of an FL taken and 3 years recommended and this can include Middle school FL courses such as Spanish 1 and then Spanish 2 and 3 in HS.
The UC’s do not see the HS transcript until the student enrolls. Everything on the UC application is self-reported which needs to match the HS transcript but there is a place to report any middle school FL courses.