Self-scans reveal that Pegasus, an invasive and powerful spyware that can secretly control phones and track owners, might be more widespread than previously thought. It was discovered on the phones of everyday phone users.
From wikiHow: How to Check Your Smartphone for Pegasus Spyware
I don’t think I saw it mentioned but if you’re already running/subbed to bitdefender av then you can install that on phone to detect it.
https://www.bitdefender.com/consumer/support/answer/1775/
I’d be careful about completely trusting any AV to give you any certainty that you aren’t infected.
As I mentioned in another comment, Pegasus is comprised of many different exploits. So just because Bitdefender can detect some older Pegasus variants, doesn’t mean it can detect all of them.
In fact it’s quite unlikely they can detect the latest variants.