Exactly. All Bitcoin ad networks are primarily intended for crypto-related sites because their advertisers are from the crypto business and it is logical that it should be so. Unless you have massive traffic, you will probably be accepted anywhere, although again you have to have at least a roughly related topic of the site. For example, if you are engaged in exercises for weight loss, crypto advertisers have nothing to offer on your pages.
You can try Bitmedia.io, they had perhaps slightly simpler conditions for accepting new publishers.
btw. OP what is your monthly traffic?