Just be there for them and support them.

I have no kids but my mom used the tactic called "I don't care about you" and it made me choose some very dangerous paths. I think a little boundaries and a nag in your teens neck is necessary , they will say "mom I hate you!" but as they grow up they will understand and appreciate that love.

We’ve all have been teens. I think we all agree guidance, advice would have been more useful than strict lockdowns.
Just make sure their partner is not more than 3 years older or younger. Talk about contraception or ask them what they know about it.