Welcome Markus,
This should confirm your posts are being seen. Second opinions are normally OK'd as a self-referral unless your insurance won't allow it. The majority of posters here over the years have been able to do this. Second opinions are great for "fresh eyes" and usually confirms a prior diagnosis. A few times they add information which is sometimes good, sometimes not so good info.
On a second opinion, I'd aim at a teaching hospital or a center that has a strong department in bladder cancer such as MD Anderson, Cleveland Clinic, Sloan Kettering, John Hopkins etc. Something must have triggered a new TURB after 5 years so keep posting or adding questions. Someone should see it and some ideas.