Loading Freestyle project config page takes longer as our promotion environments have increased over 100

Over the past year, we added more and more promotion environments ( >100) in Freestyle project job (C# projects). Now whenever we need to modify the job, loading Configure page takes longer.

I had looked into Multibranch Pipeline with declarative syntax but I don’t think the Pipeline logic meets our need because any of jobs could be potentially promoted to multiple environments over period of times.

Is there any recommendation how to approach it in our use case?

Jenkins version 2.462.3