Well, you can do all of those things, but only in Basecamp!
The XT will load the Talky Toaster maps, I’m pretty sure, and also the German gravel maps are quite good (but not at UK RoW) and will load.
That's why I insist with Basecamp. As it allows me to use the full range of features I paid for the GPS.
I use John Thorn's maps on the XT (alongside Garmin maps).
I bought TT maps years ago but ended up not using. Thorn's maps have right of way data on them, so I use them to be sure I am riding on BOATs legally.