Log out from your account and then log again. It would be reverted back to mobile version (on my case, at least)
Go to the homepage and scroll to the absolute bottom. Then you'll see some tiny words at the bottom and at the end there's "Mobile Version" written. Press that and it will turn back.
Ps. I intentionally changed my phone to desktop version to find a solution for you (=・ω・=)
Click ur pfp in top right should say moble vers
in my case there will be Mobile Version at the end of the page so just click there and it will turn back to mobile version
I accidentally turned desktop version on from my mobile but how do I turn it off