Marketing is tough

Hi everyone. We just launched our Agentic AI startup, and now are pondering over different marketing channels.
We have cold email marketing setup, but that roughly books 1 client call per week.
Google ads is getting us sign ups, but is very expensive. We tried running linkedin ads, but got zero signups from it. We are posting on youtube, and got a few signups, but that too for the free tier.
Tried launching on producthunt, got 3 signups, and 3 upvotes, because the paid marketed products hog the top spots.
Got one paying client, but that too through some b2b referral.

What do you think, where should i put more efforts in to get more paid clients?? Any channel that i am missing out?

Author: DivideSubstantial675