I would recommend an only backwards run.

I think every form of a backwards run has already been proposed.

How can we do a akina downhill backwords run

That's also been suggested lol:

https://www.speedrun.com/jelly_drift/thread/7ypqn

How can we do a akina downhill backwords run

With a mod that adds Akina Uphill https://cdn.discordapp.com/attachments/820037533835591700/830289745292427274/Assembly-CSharp.dll