Conversion rate of 40%? That’s absolutely incredible, congratulations on having one of the highest conversion rates I have ever seen in any market. With those numbers, I don’t think you need any ads at all. You are getting 4 out of 10 people that see your gig to buy, you only need about 30 hits or so a day to be rolling in clients (assuming you can even take 10 clients/day, sounds way excessive). You should get at least that just from fiverr traffic with no promotion at all.
Unless… you get that huge conversion because clicks are almost non existent, so the few that click end up buying but it’s not enough. If that’s the case, you need to change your gigs, ads won’t help.
And sure, it’s against terms of service, but even if it wasn’t - it’s a very bad investment in the vast majority of cases, simply not worth it. You are already paying the Fiverr fee for what’s essentially the lead generation - sure, you get the payment platform, messaging service, etc., but what sellers are here paying for is mostly the leads themselves.