If the taurus song had the little flourish at the end of the riff I would say Zeppelin stole it. Stairway sounds different. It’s about musical ideas. Much music can sound similar.
I agree, the riff resolves differently which gives it a different feel.
Incidentally, Clapton does a pretty close copy of the Stairway riff in his song Let It Grow. Happens around the 1 minute mark:
https://www.youtube.com/watch?v=YpDlmop0uYU
Clapton later said he copied it subconsciously.