If I equip Brutalizer to a 2 might unit by recycling a rune and then activate Jax legend ability to re-equip it, what might is my unit?

Ruling: Your unit will have 5 Might total. When Brutalizer detaches during the re-equip, the unit loses all bonuses from it and returns to base Might, then gains the bonuses again when it re-attaches.

Sequence:

• Initial state: Unit has 2 Might (base)
• Equip Brutalizer: Unit gains +1 Might (base bonus) and +2 Might (conditional effect), totaling 5 Might
• Activate Jax to re-equip: Brutalizer detaches, unit immediately loses all bonuses and returns to 2 Might (base)
• Brutalizer re-attaches: Unit gains +1 Might and +2 Might again, totaling 5 Might

Nuances:

• When a card detaches, its Effect Text becomes inactive and the top-most card ceases to have that Effect Text appended to its Rules Text
• Brutalizer's "this turn" bonus does not persist when it detaches; all bonuses are removed immediately upon detachment
• Brutalizer only ever provides either +1 Might or +3 Might to the unit it is attached to, never stacking effects