Ok, I'm fairly sure that the tenseigan is on par with the rinne-sharingan, let alone the rinnegan. Hear me out.
First of all, as many have said, the tenseigan is clearly a power buffing dojutsu, with lots of chakra given to the user. It has the powers of the byakugan, it's own reincarnation jutsus, and it's own chakra mode. If you ask me, this screams out power buff. On top of this you also get the truth seeking balls. Depending on how you look at it, you could say that this would give the user the 6 path powers, as they are basically intertwined. It also gives resistance to infinite tsukuyomi, as shown with hamura. We cannot say that this is even the full extent of the dojutsu's power, for we hardly ever saw hamura use it, and toneri was forced to battle after a very short while after he got the dojutsu, and so it is not fair to say that he could use it. Also, he lived on his own on the moon for his whole life, with no combat experience l, so, yeah.
Now, the rinne-sharingan. Since it is the parent dojutsu of the rinnegan and the sharingan (and mangekyo), it is fair to say that it has those powers. That would tlbe the ability to copy jutsus (if you have mastered their nature affinity), use eye genjutsu, mabye use a susanoo (can't remember sos), and use the 6 path techniques.
So looking at all these, I think that it is fair to say that they're both equally powerful, for tenseigan is all about huge strength buffs, shown with a new user being able to slice the moon in half, and the rinne-sharingan (Finnegan and sharingan) is all about many techniques like ninjutsu and genjutsu.
Take your pick.
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