Crowned Zamazenta has an excellent 145 in both defensive stats and an acceptable 92 HP.
It can use a rest, sleep talk, iron defense, substitute and protect
It's a steel and fighting type which gives it 9 resistances, 1 immunity and 3 weaknesses.
You didn't ask in smogon so I did it for you.
The defenses are decent on it, but the resistances mentioned don't actually impact it all that much, as out of those 9 the only type that a mon would likely rely on for all its damage output is dark with Yveltal, which can also just uturn out. Unless you're Zygarde-C, Giratina-A, tyranitar, or some other insanely fat mon with a good support movepool that can also hold an item, rest generally isn't a great form of recovery, especially with how poor Zamazenta's support movepool is consisting of pretty much nothing outside of rest which isn't great. Offensively it can't do much either with it lacking an item slot and meaningful coverage / set up options, so if it does manage to be a resting wall it can't support or deal any good damage. It wouldn't wall much outside of defensive Yveltal like mentioned, as top mons like Calyrex-Shadow, Zacian, Marshadow, Zygarde, Groudon, Kyogre, Lunala, etc. all have ways to threaten it while some like Zygarde just take no damage from its attacks. The combination of a bad support movepool and an extremely unfriendly meta keeps it out of being a good wall like it was supposed to be.
There is your answer. Hope I helped! Source