Braided Net's prevention of activated abilities doesn't prevent activating tapped rooms.
Per title, Unholy Annex can activate an unlock after being tapped with Braided Net. This doesn't work in paper.

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Rezzahan#77802 commented
Incorrect. The Duskmourn Rooms have no activated abilities to stop with Braided Net.
709.5e A player who controls a permanent that has one or more locked halves may pay the mana
cost of a locked half of that permanent to give that permanent the appropriate unlocked
designation. This cost is referred to as an “unlock cost.” THIS IS A SPECIAL ACTION (see rule 116).
A player can take this action any time they have priority and the stack is empty during a main
phase of their turn.Taking a special action is not activating an ability. So Braided Net cannot stop this in Arena, in Magic Online, nor in paper.