Between the U bolts is not going to bend an axle. People have been doing that for ages and I don’t remember anyone ever saying they bent their axle. Gets the tire off the ground with least amount of lift. If anyone thinks otherwise please tell me the physics of how that will bend the axle.
They make special “cradles” to fit bottle jacks for that purpose if you want extra support. I never used one.
I would be more concerned about using a ramp putting double the normal weight on the other one tire, wheel, and axle.