Okay so I'm onto something here.
Instead of ComboBox's I did DropDowns with the below code and set their "Items" to lookup CompanyName and JobTitle (We have several hundred job titles and some are still missing when I set it to top 500)
Sort(Distinct(Office365Users.SearchUser(),CompanyName),Result,Ascending)
Sort(Distinct(ShowColumns(Filter(Office365Users.SearchUser({top:500}),!IsBlank(JobTitle)),"JobTitle"),JobTitle),Result,Ascending)
On my gallery Items I now have the below code.
I can search from the Search bar by user name and I can filter out the results by using the CompanyName_1 drop down, however the "JobTitle_1" dropdown does not produce any results. I also think I'm very limited due to how many employees we have so I could use some help in overcoming that issue.
If(IsBlank(CompanyName_1.Selected.Result) And IsBlank(CompanyName_1.Selected.Result), Filter(Office365Users.SearchUser(
{searchTerm:TextSearchBox1.Text,top:999}),
AccountEnabled=true And IsBlank(JobTitle)=false),
!IsBlank(JobTitle_1.Selected.Result) And IsBlank(JobTitle_1.Selected.Result), Filter(Office365Users.SearchUser(
{searchTerm:TextSearchBox1.Text,top:999}),
AccountEnabled=true And IsBlank(JobTitle)=false),
!IsBlank(CompanyName_1.Selected.Result),Filter(Office365Users.SearchUser(
{searchTerm:TextSearchBox1.Text,top:999}),
AccountEnabled=true And IsBlank(JobTitle)=false And CompanyName = CompanyName_1.Selected.Result))