Best anti-theft ways to carry a phone?

My phone was just snatched right out of its case while it was on a neck strap in Paris.
I’m looking for a much more secure solution for the future. My main issue is that most of my clothes don’t have functional pockets. I’m considering crossbody bags or fanny packs, but I’m worried about them being unclipped, cut, or simply opened without me noticing.

I really need something where I can actually feel the phone against my body. I want to know it's still there without having to constantly check the bag. Does anyone have any recommendations? Thank you!