I think it makes sense for this to be “as soon as possible”. Changes to the lists take some time to take effect and are “broadcasted” before the change takes place due to the governance mechanism around them.
Changes to the lists, especially before the process can be Easy Tracked (see here Lido on Ethereum: Relay Voting Proposal - #4 by Izzy) will be slow enough that Operators should be able to react timely even if relay lists are configured manually. If eventually the mechanism is Easy Tracked and thus sped up, I anticipate that Lido contributors and/or Node Operators will have developed tooling that allows them to easily reflect necessary changes.