Chances of getting into UC Davis, UC Berk, UCLA

Hi
My unweighted uc gpa is 3.43 and weighted is 3.79…
ACT is 30 i have one chance left
My extra curriculars are playing piano for 9 years, passing level 10 in Certificate Merit, playing tennis for four years (varsity 3 years), chamber choir for three years, volunteering at kaiser hospital, NHS secretary, President of a club…
Im applying undecided
took 1 AP sophomore year, 4 APs junior year, 3 APs senior year

Your UC GPA is low for the top and mid-tier UC’s since the average is 4.0 and UC’s are very GPA focused. Your ACT is within range and going Undeclared gives you no less or no better advantage than just selecting a major (unless highly competitive).

Here is the UC admit rate based on UC GPA (capped weighted) and not major specific. Make sure you have some solid Match and Safety schools on your list since the schools listed are not in this category. Consider adding UCR and UCSC along with some Cal States.

Freshman admit rates for UC GPA of 3.40-3.79:

UCB: 2%- High Reach
UCLA: 3%- High Reach
UCSD: 6%
UCD: 15%- Reach
UCSB: 14%
UCI: 13%
UCSC: 59%
UCR: 78%
UCM: 92%

25th - 75th percentiles for ACT:
UCB: 30-34
UCLA: 30-34
UCSD: 29-34
UCSB: 28-33
UCD: 26-32
UCI: 26-32
UCSC: 26-31
UCR: 23-30
UCM: 20-27

really slim… be sure to apply broadly. SDSU UCR and CSULB are also worth an ap.
good luck