While Vehicles are a fun thematic element, the Modules self-mill and crew requirements dont align with the decks counter-focused identity
The important phrasing here is once it's resolved. If you play a flash creature during the attack phase before blockers are assigned, then yes, you can block with it
For most other decks, The Masamune is going to be quite situational and falls lower in the pecking order of powerful Equipment
"Planar Portal" has more opportunity for power creep to factor into its gameplay, but "Merciless Rage" is more focused on one specific mechanic whereas "Planar Portal" has roughly three to consider
Disney Lorcana: The First Chapter Booster Pack (One Random Pack)
Flubs, the Fool Commander decks want to utilize graveyard synergies, thats for sure