Day trip to saint tropez - ideas?

My wife and I are traveling from marseille to nice in 2 weeks and want to stop for a full day in saint tropez.

We’d like to have a nice sit down lunch and a beach experience.

Where can we go for lunch that would give us access to the beach without a high spend requirement?

Are there any thing we must do if we’re there? I’d like to see a great view for sunset.

Any recommendations?

🙏🙏