D&D 5E Do the effects of the Haste Spell stack with the Fighter's Action Surge feature?

[Oofta]

The variant feat the OP is using grants 2 off-hand attacks.

Ah, I was using the official version.

Dual Wielder​

You master fighting with two weapons, gaining the following benefits:​

• You gain a +1 bonus to AC while you are wielding a separate melee weapon in each hand.
• You can use two-weapon fighting even when the one-handed melee weapons you are wielding aren't light.
• You can draw or stow two one-handed weapons when you would normally be able to draw or stow only one.

 

[pnewman]

I thought that the rules from Fizban's were only for Dragonborn from Fizban's and not for Dragonborn from the PHB. I know Monsters of the Multiverse races supercede previous sources but is there a canonical declaration that Fizban's races do so as well?

 

[Paul Farquhar]

I thought that the rules from Fizban's were only for Dragonborn from Fizban's and not for Dragonborn from the PHB. I know Monsters of the Multiverse races supercede previous sources but is there a canonical declaration that Fizban's races do so as well?

There's a canonical declaration that there is no canon.

It's up to individual tables to decide what rules they use.