Forgot this is an ODTA filter query!
Correct way to check if a value is in a column, is: contains(Column, 'value')
So could you give this a whirl and then let me know what Power automate receives? It should be:
(startswith(EquipmentType, 'your value')) and (contains(Title, 'your value'))
Throw it into a Context Var for now and check what's inside it.
UpdateContext({varTemp: ExportTaskEquipment.Run(
"("(startswith(EquipmentType, '" & drpEquipmentChoice.SelectedText.Value & "')) and (contains(Title, '" & txtEquipmentFilter.Text & "'))",User().Email)})