Stop thinking about refusal. If I thought that your app had any chance of refusal, I would tell you. You have been together for a few years and are living together. You are fine.
It seems like those with the least chance at getting refused are the ones who worry the most! You have quite a lot of proof and you don’t have a ton of warning signs. Long relationship, plenty of in person visits, not immediate marriage, you are educated, assume you are similar age, etc.