The Decay timers are supposed to be there to eliminate inactive structures.
Instead they discourage casuals from investing time and have legacy players logging onto multiple servers simply to refresh their belongings every week for 5 minutes.
Neither of these outcomes is desirable. Legacy players should be able to Prestige out of their current holdings to slowly build up an option to skip levels when they hop on an official server. It would have a limit to how many times it could be used (Week, Month, or Year) but it would encourage people to stick around long enough to complete playthroughs so they could advance their ability to quickstart on a new server.
There could also be a bank/credit system of resources that would be part of the prestige system, so people could jump right into building on a new server. Again, this bank/credit would have some sort of reset timer to prevent overuse… it would be a strategic/leisure resource, depending on the playstyle of the account holder.
They could make prestige leveling separate between Exiled Lands and Isles of Siptah if they want to protect the freshness of new content.