Go where people are searching for help. Indiehackers, Twitter, Upwork codementor, railsdevs.
I think the key is not necessarilly sharing your past work but rather what you can do for them.
Relying on your experience will help you greatly if you were joining another startup, but as a freelancer you are specifically doing a very itemized job.
I've been consulting for 18+ years.
My best projects/connections have always came through my network or a community group for something like a framework (Rails/Laravel).
It's all about who you know, who knows what value you offer and them connecting you with someone who needs that value.
Get out there and make connections.
It’s probably a bit late, but the path you should have taken was - “I’ve got some/a potential client - I should go freelance” not “I’m going freelance, now let me find some clients”.
You’re competing against a huge number of outsourcing firms for attention. I get emails and LinkedIn messages all the time pitching services.
Good luck.