Bitcoin in private wallet cannot be "grabbed" by a third party. You must give them your keys for them to be able to move it off the wallet into usable form. They can always physically grab your private wallet, but cannot use or transfer the Bitcoin, ever. All cryptos, including Bitcoin on a public exchange can be stolen, just like anything else (under guise of law enforcement or "regulatory noncompliance", take your pick).

Current problem with Crypto exchanges is KYC, Know Your Customer. You can open an account without a digital ID, but if you want to move Bitcoin off the exchange to a private wallet, you are FORCED to do a digital ID so your Bitcoin is all then physically traceable to your home address.