You can also change your Reddit settings to use the old UI for www.reddit.com.
Only if you're logged in, though. (I believe?)
It doesn't work on mobile though.
What do you mean?
Even if you set your preferences to prefer old.reddit.com style, the reddit website will only respect that when accessing from a desktop device. On a mobile device you always get the "new" reddit.
Ohh okay. I skipped a comment in the chain and thought you meant either the redirect on Kagi doesn't work on mobile, or the old.reddit.com site doesn't work on mobile.