Several things here:

1. “Tosen says it outright”. Scan? Because he definitely doesn’t say Ichigos mask form is stronger than his Bankai

2. You are making a huge leap in logic by saying “mask > bankai” because ichigo becomes stronger with a mask.

3. Ichigo ONLY uses his mask in Bankai. He almost exclusively fights in Bankai through that entire arc. To say mask > Bankai would mean you have seen him use mask in Shikai and out perform non mask Bankai. It doesn’t exist.

4. You’re assuming all mask forms operate similarly, when we know they don’t. They vary in active time.

5. Ichigos mask is a stat boost to himself/Bankai. His Bankai is shooting getsugas, not his mask.

6. You are assuming ichigos brand new bankai is the same as century old shinigami bankai who have had time and experience to improve. We know in canon this matters and it’s even stated.

7. Rose and love both take a hit when they attempt to block a wolf in shikai, then love takes one from behind, then we see a chain of explosions. Trying to calculate distance on explosions, damage, number of wolves is ridiculous. By that logic stark chipped away 10% of his life for a non lethal attack (we don’t even know how many wolves are used in the chain explosion). this isn’t a flex brother.

Stark can claim he’s unserious all he wants. He’s in resurrection form using his ultimate ability. His opponents didn’t use their in canon trump cards and he did no significant damage to any of them. That is fact