Currently it is not possible to filter on a Sharepoint lookup field in the Get Items (Sharepoint) action. Please implement.
This is really unhandy because now we need to
(a) create an additional plain text column with duplicate data inside a SharePoint list or a parent-child list to replace the lookup column (potentially causes inconsistent data) so we can filter directly in "Get Items"
(b) or we need to loop each entry inside the list in the Power Automate Flow and compare to a value which causes loads of unnecessary actions and possible throttling issues if the Sharepoint list contains a lot of rows.
I already had a remote session with a power automate expert from Microsoft on this. We tried all different combinations in the ODATA filter like field/value or 'field' or 'field/value' and so on but it did not work.