No more ambush, new rule forces teams to let the other team know they are doing an onside kick

Not really, they are trying to put some back into it. Onside kicks haven't been a thing for quite a while and now they are putting a play in place that gives teams the opportunity to try one. Also, they are bringing back a version of the kickoff, I think it's what the XFL did. So these rule changes are good for the league since the kickoff part of the game has been boring af lately.
Yeah, I think people on this thread are mostly reacting without being fully informed.

The NFL kickoff (which occurs on average roughly 9 times per game) is dead, and they’re working on finding a way to bring it back.

If the price tag is giving up the surprise onside kick, a play that occurs maybe a handful of times each season, it’s positively worth it.