Unfortunately your link to the SDK topic does not help me in any way. I am just a normal user of flightsim products and not a software freak, so I can tell you that I never messed around with any SDK's not in MSFS 2020 and also not in previous flight simulators.
The link explains exactly the problem, and nowhere I said YOU should "mess with the SDK", something you can't do it yourself, since you don't have the source file for the airport.
What the link is saying, is there's a BUG in the *current* SDK, which results in ILS not being compiled correctly, unless the scenery developer unflags the option to remove the default ILSs, which would be wrong as well, since it will end up creating an intentional double ILS conflict.
So, you are saying our update "caused" the problem but the issue is, the SDK is not something you can choose which version to use, because what compiles the scenery is NOT the SDK ( which is just a collection of Documentation and 3DS plugins and samples ), it's the SIMULATOR ITSELF so, as you surely know, when there's an update of the simulator, everybody gets it at the same time so, it's not as if we could have possibly release an update to Zurich made with an "old SDK", one that didn't had this bug.
So, the only option is for Asobo to fix it, wait for the new version of the sim to be out, so we can recompile it again, and release another update.