Evidence of remote access to iPhone

Unless you are a high profile target, such as a diplomat, political figure, celebrity, journalist or other high valued target, that sheer time, money, tech and knowledge required for thus. makes such attacks on regular folk completely unlikely. You are just simply not worth the time, money or effort required. The hackers they want targets that will provide a large reward for doing it.

If you have not done so, or do not know what jailbreaking is, then it's supremely unlikely anyone has remotely accessed your iPhone. There's also no way to tell as such hacks are meant to be covert and not advertise themselves.

if you suspect someone has remotely accessed your phone, change your Apple account password to lock them out.

The current version of iOS is 27.2 at this writing. Keeping up to date helps deter attacks.