If you get to Riga, let us know.
I have not transitted the Russian waters off Kaliningrad myself, but I have heard a number of bad stories and no good ones. The area has very high military significance, I think the entire area is a military exercise zone, and there are many stories of yachts being chased out of those waters, rights of innocent passage
be damned. Same thing with the Russian islands off the Finnish coast. I think the theory is that the high military significance means innocent passage is not possible. I would steer a wide berth myself. From Germany
I think I would go to Gotland, and then hop across from there.
It is otherwise if you are following the normal marked channels to St. Petersburg or to Vyborg, with appropriate Russian visas. Russian CG very friendly, as are the customs
and passport control people. Vyborg highly recommended; one of the most interesting places we visited in the Baltic
I think if you were actually sailing to Kaliningrad and possession of Russian visas, that would probably also be fine. Following the recommended route
strictly! It's transitting through their military exercise zones which, apparently, makes them crazy.