You have to ask permission before unloading on others. I can't stress that enough. It's not fair to people when you move straight to telling them what's happening with you without asking them if they're in space to receive your energy or giving them room to decline.

How you should slide in people's DMs when asking for advice:

Hi (name),

I hope you're doing well. I would love to ask you a question concerning a situation in my life when you have the time. I feel like you might be the best person to help me with this.

Thank you,
(your name)

Most people who come to me for advice about someone's who's not respecting their boundaries, taking them for granted, don't realize that from the moment they enter my DMs, they do the same to me. They lead the way without making sure I agree to participate in the exchange.