Filter a directQuery with parameter and apply parameter change within URL call (PBIRS sept2021)

Unfortunately what you are trying to do is not possible. Currently the parameters in a query can only be changed at "design time" (while editing in Power BI Desktop) and cannot be changed dynamically while viewing a report. 

One other approach would be to include all the rows from your User table, then apply the url filter using the filter= syntax as documented here https://docs.microsoft.com/en-us/power-bi/collaborate-share/service-url-filters 

Another approach could be to look at using Row Level Security to filter the user table, but you would need to have some way of mapping to a login to one of your user ids in order to do that.