is it okay to undervote?

3rd time voter here; i have a list for senatorials already pero I'm feeling little to no hope lang sa local elections dito :'D kumakapal mukha yung former mayor namin and our current mayor isnt kinda doing well rin. im planning to only voting for 1 councilor lang sa amin (or more if may nakitapa akong competent/worthy talaga)

is it okay to do such thing?

(if curious, taytayeño po ako :'D)