Be careful, there have been some pretty nasty 0-click exploits in the time Android 11 has been around, so I hope you have still been getting security updates.
In about 5 months, Android 11 will be end of life and won't get security updates anymore, so definitely keep an eye out for anything you may be vulnerable to.
Of course, Android 11 is still supported as of right now, so if you have been getting security updates when available, then you are good. I just know there are phones running 11 and below that don't even get security updates, so those are the people that need to watch out. You can check your Security Patch Level in settings to be sure.
I'm still on android 10 over here. I hadn't even looked until I saw this. Are you saying it's better to get a new phone, rather than just a new battery for my S9?
If you haven't been getting security updates, I would definitely consider getting a new phone. Especially if you are not one that stays home a lot. The people who will try to exploit things like Bluetooth will be out and about, not walking up to your home.