This is valid OpenAPI because all the paths can be resolved unambiguously. However, cannot create two indexers.
We have a few options:

• For languages without indexers we can change GetById to be GetByParam1 and GetByParam2. However to ensure we are deterministic we need to change this for all cases even if there is only one indexer.
• For C# we either drop indexers, we find a deterministic way of picking which parameter will use the indexer, or we mash the two parameters into one and split them back apart if necessary.