FB uses a rather obscure and proprietary internal scoring system. You may be able to publish an ad campaign with lots of text once or twice, but it will make your ads account score go down and at some point it will likely be disabled - temporarily first, after one or two more incidents forever.
The recommended amount of text on the image is less than 20%. Their system also doesn't like text because of potential "circumventions of policy" with putting text in images. Weird fonts that are not machine-readable will likely get the account banned fast.
This actually matches with my experience. My product is text-related and I ran a couple ads with allowable amounts of text (back when there were limits). The ads performed just fine, but FB decided to stop running them, claiming they were low-quality.
The recommended amount of text on the image is less than 20%. Their system also doesn't like text because of potential "circumventions of policy" with putting text in images. Weird fonts that are not machine-readable will likely get the account banned fast.