Need help on this topic, I got 2 Germans route HRR and HBK not showing up in the route selection, but what is more strange is that the BR 218 and BR 101 layers shows up on other maps like Frankfurt-Fulda.
I've got a similar problem where I've downloaded some TSW5 compatible routes but they download and do not show in the game. Very odd... A few routes download successfully but others download but don't show up. On PS5 also.
Not sure if this helps you, but I had a whole bunch of add-ons actually listed in TSW5 (under Manage Game Content) that weren't a there in the game. Only the core TSW5 add-ons were. So I went and deleted all the old add-ons that I didn't see and added in the ones I wanted to play. Everything is OK now, though it'll take me a while to get completely up to speed with all the additional locos.
Every time I download DLC I have to restart the game to make the DLC available in the game. This i had to do for TSW4 too. Besides that, all DLC is marked as "New" although I have used them for quite some time. Same on TSW5.