Oh, and if you think a Barbarian/Monk multiclass is actually inferior to a pure-classed Monk...
Getting Rage damage on Unarmed Strikes even with DEX is a greater damage increase than each step of the Martial Arts die and gives greater benefit to the Monk with their bonus-action attacks than it does for a pure Barbarian.
Deflect Attacks has obvious synergy with Rage reducing bludgeoning/piercing/slashing damage.
Evasion has obvious synergy with Danger Sense.
A Barbarian/Monk can use the Barbarian's Unarmored Defense for DEX/CON instead of DEX/WIS, as Stunning Strike doing damage on a successful save actually provides a benefit to low-WIS Monk builds.
You are right that Barbarian 1 / Monk 1 is an offensive powerhouse capable of dealing 2*(3+2+1d6) +2+1d6 = 22.5 damage in tier 1.
Could you explain your math?
I think.... they have a short sword or scimitar weapon mastery. They are using strength so they are getting the rage bonus. Their weapon has the nick property.
So attack 1 with whatever is 1d6+str+rage or 1d6+3+2, second attack is bonus action attack which is the same 1d6+3+2, and then the third attack is nick attack that is just 1d6+rage because you don't get your strength bonus to light weapon attacks unless you have the two-weapon fighting style which barbarian doesnt get. Take the average of the rolls and you get 3.5 per roll x3 = 10.5+ all the bonuses for 22.5. Now, of course this doesn't take into account hit chance or crits at all, but I think that got us to his numbers.
I think.... they have a short sword or scimitar weapon mastery. They are using strength so they are getting the rage bonus. Their weapon has the nick property.
So attack 1 with whatever is 1d6+str+rage or 1d6+3+2, second attack is bonus action attack which is the same 1d6+3+2, and then the third attack is nick attack that is just 1d6+rage because you don't get your strength bonus to light weapon attacks unless you have the two-weapon fighting style which barbarian doesnt get. Take the average of the rolls and you get 3.5 per roll x3 = 10.5+ all the bonuses for 22.5. Now, of course this doesn't take into account hit chance or crits at all, but I think that got us to his numbers.