is it actually true that can i use competitor brand keywords in google ads?

both of you are half right. you can bid on a competitor's brand name as a keyword, google allows it. what you generally can't do is put their trademarked name in your ad text, they can file a complaint and the ad gets pulled. whether it's worth it is another matter: quality score will be poor, so you pay more per click, and conversion is usually weak because people searching a brand name want that brand. and they can do the same back to you. test it with a small budget and a landing page that explains why you're the alternative, and watch the cost per lead honestly.