Dynamic Variable in Measure

Hi, PowerBITestingG 
I think here is the problem:

VAR octoberstart1 = SWITCH(TRUE(),
[MaxOctoberStart]=10/03/2022,"10-03",
[MaxOctoberStart]=10/04/2021,"10-04","10-03")

The 10/03/2022 is probably not recognizable because it's not either string or number, so you have to wrap it with "" to make it a string and then make sure, that MaxOctoberStart returns a date in same format.
Or you can check against DATE function and fill it like this:

VAR octoberstart1 = SWITCH(TRUE(),
[MaxOctoberStart]=DATE(2022,3,10),"10-03",
[MaxOctoberStart]=DATE(2021,4,10),"10-04",
"10-03")