Here is the process that is working really well for us:

1- Use a backlink finder tool, like bestseomarketingtools(com), to find hundreds of domains in our product niche

2- Filter by the domains with similar DA as ours

3- Export the list of potential websites to a tool like Apollo and start a sequence asking for an exchange

PS: If the 101 exchange email does not grab their attention, you can also create a listicle of the top X tools in that niche and ask them if they want to be part of it and then ask for the backlink.

Let me know if this is helpful :)