Is a complaint reasonable after 13 weeks? Spouse Visa Uk Standard Outside (Germany)

Does someone know if I should send now a complaint?

13 weeks are over now and 2 paid enquiries didnt help at all. They didnt request further documents and our case (especially the finances) are very straight forward. Got approved a Marriage Visitor Visa last year as well with no issues.

Just wondering if the complaint has any negative impact on our application? thank you.