Eight months is brutal. Yet that isn't even one leg of a round trip Mars mission, unless nuclear propulsion is used. Still a giant problem we have to figure out. We are not colonizing the solar system of chemical rockets alone.
We don’t just need better propulsion. The human body needs gravity. Not to mention shielding from radiation. Both of those things are doable, but I doubt there’s the political will in Washington to keep astronauts safe. If China planned on sending people to Mars in the future then America would strap a few people into a rocket propelled shoebox and honor the completely broken human when/if they get home.
Maybe they can just tether two ships together and have them rotate around a common CoG like a bucket swinging around on a string. Wouldn't be that expensive. The radiation I'm not sure, maybe they can create a "safe room" on the ship surrounded by their water reserves.
The tether thing is so simple I'm surprised it wasn't in use decades ago. I think I remember them confirming it being a viable option on Gemini when they tested it being tethered to the test vehicle.