Is that bottom connection correct for a ring oscillator? Or are there better ways?

That works, but since a ring oscillator needs to be carefully calibrated for frequency, you'll need to be aware of the high resistance of the local interconnect lines. It would be better to run the feedback in metal1.

Okay, I did face tht problem since my simulation outputs a straight like with negative slope. I will connect it with m1 and see how that goes. Thanks @User