Happens to me too. Happens to everyone. The radio stations suck! There are always like a couple dozen songs maximum that just get repeated randomly.
I created a new station based on a temporary playlist with a couple of songs and I would love to hear similar artists and maybe some of the other songs of the artists in the playlist, but what do I get? Only the same songs again and again. Of the artists in the playlists I never heard a different song than those in the playlist already.
The radio really really needs a "dont play this song for a while" button or just an option to increase the variety of the music pool.
This is a problem for more than half a decade now and spotify isn't doing anything
I found a workaround. Instead of using Radio just create a playlist and scroll down to recommended songs for this playlist and just add all of them until you have 10 hours of runtime and voila, you have a radio without repeating songs and if there are songs that you dont like you can remove them or just not add them in the first place.
It's not perfect but certainly better than that shitty radio system