The first filter hides the Recommended Channels in the sidebar and the second hides both Recommended and Popular Channels. They also work for the collapsed view.
www.twitch.tv##div[aria-label="Recommended Channels"] www.twitch.tv##.side-nav-section:nth-of-type(2)
I have been using these filters since beginning of December 2020. They are still working for me as of 1/14/2021.
uBlock Origin: 1.32.4
Microsoft Edge: 87.0.664.75 (Official build) (64-bit)