Cold DMs in a niche like ITAM? Might as well shout into a pillow. The people who actually care about asset management and audit cycles aren't scrolling LinkedIn waiting for your "disruptive solution" - they're buried in spreadsheets and muttering about Snipe-IT's API limits.
What actually worked for me was lurking in the three or four corners of the internet where these folks whinge about their current setups. Think r/sysadmin, r/ITManagers, the old Spiceworks forums. Don't pitch. Just show up and answer the boring questions - "ServiceNow ITAM pricing", "how to survive a Microsoft license audit", "why Snipe-IT chokes on 10k assets". After a few weeks, people start DMing you asking for your thing.
Here's the kicker: offer to do the implementation yourself for free for the first three design partners. At MVP stage you need feedback loops, not logos. Most ITAM professionals won't touch unproven software unless you're basically living in their Slack for a month.
Are you defining "beta tester" as someone who pays, or just someone who shows up?