What are some good ways to find users to fill out a user research survey form?

Hey folks!

I'm currently working on iterating MyCheckins based on the lessons learned from user interviews over the last 10 days.

I have a (pretty decent) hypothesis on the direction I want to head into next, but I want to validate that with a larger pool of users before getting back to development. I'm hoping to get this validation via a simple Google Form. However, I'm struggling to find people who can fill out the form.

My target audience is Slack users. Not hard to find. But I'm struggling to find a good way to reach out to people beyond my network (which is super important). I put up some posts on Reddit, engaged with a few people on comments, and got some responses. I'm also thinking of Twitter. Just wanted to hear if you guys have done something like this before.

1. Do you have any experiences, tips, or advice to share when it comes to cold outreach for user research?
2. How do you ensure that you're not being spammy to someone? [my biggest concern]
3. What channels or processes have worked for you in the past?

Also, just putting this out here in case you use Slack/MS Teams and would like to help - Quick Feedback Form (1-2 min) (It's only a couple of minutes long and you don't have to share any personal info)

Thanks!