So long story short I've worked with proprietary software X for a long time, and specifically I do a lot of work investigating the SQL database for software X. Writing custom reports, making queries to find problems, the like.

Small to VERY large companies use this software. I'm afraid I'm on the small side so I'm unknown to the community of users and my name wouldn't carry weight.

I feel confident that any report someone asked me to write, I could write and I can write scripts to help businesses find issues they aren't aware are costing them money.

Like there is an issue that if you find it you need to call support asap to get fixed or statements go out with incorrect amounts on it, but the software doesn't warn you, you have to just notice that the balance on the statement you are sending out doesn't "look right" then call support and have them confirm or not. But a query I have will tell you right away, so running it right before running statements makes a world of difference.

But like... how do I even start? Do I just need to start cold calling companies that based on their name "might" have this software as well, and explain my case?

Do I make a website pretending I've been doing this for years, then send out an email being like "Y consulting is now accepting new clients who use software X, check out some of our most popular custom reports, then fill out this form to get a quote for one of your own!" to just every person in the industry and hope someone actually reads the email?

Should I make a blog with free reports, email that out to people, then have a mention that for custom reports I'm for hire?

Like the more I think about it the more this feels like it's probably more of a reputation thing then anything else, so I have no idea where to start. Are these awful ideas? Does anyone have advice for it?