I'm experiencing the same issue. I think it started happening sometime this week. And it's not just the featured slider; it's everything on the front page.
Hello @LiamDawe, are you still experiencing this issue on an up to date system? If you are, please double check that your platform preference is set the way you want at Steam -> Settings -> View Account Details -> Preferences -> Platform Preferences.
Thanks for checking in with me, can't say I've had this issue in a long time.
Nothing extracted yet.
Weirdly, the featured slider on the homepage has now begun constantly showing me Windows-only games, and saying "recommended for you".
It used to only show games that are on SteamOS/Linux, I consider this a really annoying bug. Happens in both the client and web browser.