Not a teenager but need help with one

I'm mid 20s, and need help with my 13/14 year old sister. She is comfortable with talking to me, and yesterday said some extremely worrisome things.

Mum and I want to reduce her internet access and monitor it.

Please do not judge for this not happening sooner, we work 40+ hours to provide for the family.

How can we go about this without making her resent us. What are some healthy outlets we can replace this with?