How do you leave Bitcoin in your Will without risking someone taking it?

I’m thinking about getting into Bitcoin and want to understand how it could passed on in the event of my death, without the risk of it being accessed while I’m still alive.

My biggest concern is this: How do you securely leave your seed phrase/private keys or access details to someone (like an executor or family member) without them being able to access or steal the funds prematurely?

What do you recommend for someone who wants to:

1. Keep control during their lifetime

2. Ensure smooth access by loved ones or executors after death

3. Avoid technical risk and legal ambiguity

Open to all ideas, DIY setups, legal strategies, or even trusted third-party solutions.

Thanks in advance!