You can generate more than the intended 100 gold units/minute by using one monk and 3+ monasteries.
Video link proof: Age of Empires 4 - Relic Bug Exploit: Fast gold with 3+ monasteries (NOT the RUS duplication bug) - YouTube
Steps to reproduce:
- Build 3 monasteries very close to eachother
- Deliver a relic inside the first monastery
- Pick up the relic with the monk, by right clicking the building, the relic will get in the monk’s hands
- Place the relic inside the adjacent monastery, the second one
- Pick up the relic again from the second monastery, place it in the third one
- Repeat the loop
I managed to get nearly 240 gold units in one minute, but I am pretty sure you can do better.
P.S. please remember to update AOE1:DE too, we are waiting for fixes and balancements!