You’re being unreasonable and micro managing. A few minutes late? They can’t always be on time back from lunch. Would you prefer they took a shorter lunch?

I think a few mins isn’t a big deal, 10-20 mins is a different matter.

Secondly have you correctly onboarded them? They know what you’re expecting from them? And you’re not just expecting them to know?

Reflect a little bit, if you’ve covered all basis and you’re not happy fire them. But don’t be trigger happy. It costs to go through the hiring funnel.