Been there. If you’re starting off without a site, your Telegram channel is your storefront so treat it like one. Post consistently (even if it's just value tips, proxy use cases, or news), and make it feel active.
Telegram ads can work, but most channels are botted to death. What helped me early on was buying shoutouts from niche-related groups (e.g. sneaker copping, automation, scraping) where people actually need proxies. You’ll get less fluff traffic and more folks who convert.
Also, try cross-promoting with small but legit proxy or tool channels. Offer a cut or free proxies in exchange that stuff scales better than paying for cold traffic every time.
Long-term though, building a landing page or even a Notion site for SEO juice + trust will help. A lot of people hesitate to buy just off a Telegram username.
Just my 2¢ keep testing and see what brings the warmest leads.