In a court case with the Federal Trade Commission, Google said the following:
"The ranking itself is affected by the click data. If we discover that, for a particular query, hypothetically, 80 percent of people click on Result No. 2 and only 10 percent click on Result No. 1, after a while we figure probably Result 2 is the one people want. So we'll switch it."
A Google search quality employee, Edmond Lau, said something along these lines also:
"It's pretty clear that any reasonable search engine would use click data on their own results to feed back into ranking to improve the quality of search results. Infrequently clicked results should drop toward the bottom because they're less relevant, and frequently clicked results bubble toward the top."
There are also businesses that make your CTR higher through actual humans clicking on your result. Supposedly, it does indeed work -- but when you stop the service and your CTR decreases, you drop back pretty quickly.
So these reasons, I do believe CTR is a ranking factor, yes.
A great article on the topic which is definitely worth a read: https://www.link-assistant.com/news/user-behavior-and-seo.html?__c=1