I built a prototype and shared it travel/immigration subreddit. Note, my product is 100% free, no-login and (most importantly), solves a pain problem in a niche.
There's a paid version (https://plus.fillvisa.com/) for Immigration professionals. Tbh, I don't directly market it that much.
I also decided to open-source Fillvisa (https://github.com/athos2113/fillvisa-os) . Can't say it has directly helped in acquiring users, but, it defintely helped buid trust, brand credibility.
So, my actual product is B2B or B2P (Prosumers). I decided to build a ungated free B2C solution And, also an open-source version