I have a Power App which is using 2 lists, 'Projects' and 'Shocs' (This is a checklist with tasks to complete). 'Projects' contains the Oracle project number, Project manager, due date etc. A project will have a checklist (Shoc) linked to it and the checklist looks up the project info (project name, project number etc.) from the related Project record but, due to SharePoint limitations (Solved: Lookup Person columns from another SharePoint List - Power Platform Community (microsoft.com)), it can't have a column that looks up the Project manager as that is a people picker. We also cannot use a text field which we write the Project Manager's name to on creation as the Project Manager can change and needs to dynamically update throughout the app.
I have a gallery which shows all the current checklists (shocs) and I currently filter by 'status' using a dropdown and also by project number using a TextInput box. This works fine however, the end user now wants to filter by Project Manager instead of Project Number but I cannot seem to get this to work.
In the gallery, the Project manager is shown in a text label using the code below and it displays the Project Manager correctly. I've tried adding the code below in to the filter in place of the Oracle project number but I keep getting errors.
LookUp(Projects,'Oracle Project Number'=ThisItem.'Oracle Project Number'.Value,'Project Manager'.DisplayName)
Here is the original code that filters by status and Oracle Project Number:
SortByColumns(
AddColumns(
Filter(
Shocs,
DropdownSHOCStatus1.Selected.Value = "All" && TextSearchBox1_3.Text in 'Oracle Project Number'.Value || 'SHOC Status'.Value = DropdownSHOCStatus1.Selected.Value && TextSearchBox1_3.Text in 'Oracle Project Number'.Value
),
"OracleProjectNumber",
ThisRecord.'Oracle Project Number'.Value
),
"ID",
SortOrder.Ascending
)
Here is an image of the code I've tried to show the problem areas. I've tried variations of this without success. Can anyone suggest a way I can filter this gallery on the Project Manager value instead of the Oracle Project Number?

I hope this makes sense but let me know if more information is needed.
Thanks.