As Shirokami and to some extent I try to say, this game is not a holy trinity game. Bosses, the actual meat of the content, are not held nor guided by tanks. Sure, you could grab their attention for the whole fight, but most of their attack kit will still reach all or most of the group fighting it.
In holy trinity MMOs, a tank is used to make the boss use many of it's attacks on the tank or the area the tank is at, while leaving his flank free for the dps to attack without the risk of being hit themselves. Some attacks are AOE in those games, to wake up the DPS and healers. But for the most part, it's the tank's job to keep getting the hits. This doesn't quite happen here in PSO2. So for the most part, any damage a "tank" will block/evade/absorb, the rest of the players will also need to deal with it.
So in the end, you can make a tanky build, but only to benefit yourself. If you are still onto it, make it in a way that doesn't sacrifice damage, or you will be less useful to a party because of sub par performance.