How to filter a gallery via a drop down selection fed by a lookup column in Power Apps

I am VERY new to powerapps. I'm completely self-taught through youtube and have no programming background, so things need to be dumbed down for me.

Here is my setup. I have a main sharepoint list that most of my data is pulling from titled "Combined Inventory List". I have a lookup column on that list called "Mfg" and I have pulled in "Mfg:Title" by the settings of that lookup column.

In my powerapp, I have a series of dropdowns to filter my gallery on that "Combined Inventory List".

The following has worked for the non-lookup columns:

Dropdown:

Choices('Combined Inventory List'.'Mfg:Title')

Gallery:

Filter(
        'Combined Inventory List',
        IsBlank(ItemTypeDropDownBox.Selected.Value) || IsEmpty(ItemTypeDropDownBox.Selected.Value) || ItemType.Value = ItemTypeDropDownBox.Selected.Value, 
        IsBlank(BrandDropDownBox.Selected.Value) || IsEmpty(BrandDropDownBox.Selected.Value) || Brand.Value = BrandDropDownBox.Selected.Value, 
        IsBlank('Style#DropDownBox'.Selected.Value) || IsEmpty('Style#DropDownBox'.Selected.Value) || 'Item#'.Value = 'Style#DropDownBox'.Selected.Value,          
        IsBlank(ColorDropDownBox.Selected.Value) || IsEmpty(ColorDropDownBox.Selected.Value) || Color.Value = ColorDropDownBox.Selected.Value,
        IsBlank(SizeDropDownBox.Selected.Value) || IsEmpty(SizeDropDownBox.Selected.Value) || Size.Value = SizeDropDownBox.Selected.Value,
        IsBlank(Garment_Build_Dropdown.Selected.Value) || IsEmpty(Garment_Build_Dropdown.Selected.Value) || GarmentBuild.Value = Garment_Build_Dropdown.Selected.Value,
        IsBlank(Group_Dropdown.Selected.Value) || IsEmpty(Group_Dropdown.Selected.Value) || Group.Value = Group_Dropdown.Selected.Value,
        IsBlank(Mfg_Dropdown_1.SelectedText.Value) || IsEmpty(Mfg_Dropdown_1.SelectedText.Value) || Group.Value = Mfg_Dropdown_1.SelectedText.Value
        )

I can't seem to the filter to work with the mfg column.

I thought that using the "Mfg.Title" column would help because it would be a text only value but that doesn't seem to be the case.

Can someone help me figure out how to make this work?

Thank you!!!

Try using formula like this:

Filter(
	'Combined Inventory List',
	IsBlank(ItemTypeDropDownBox.Selected.Value) || IsEmpty(ItemTypeDropDownBox.Selected.Value) || ItemType.Value = ItemTypeDropDownBox.Selected.Value, 
	IsBlank(BrandDropDownBox.Selected.Value) || IsEmpty(BrandDropDownBox.Selected.Value) || Brand.Value = BrandDropDownBox.Selected.Value, 
	IsBlank('Style#DropDownBox'.Selected.Value) || IsEmpty('Style#DropDownBox'.Selected.Value) || 'Item#'.Value = 'Style#DropDownBox'.Selected.Value,          
	IsBlank(ColorDropDownBox.Selected.Value) || IsEmpty(ColorDropDownBox.Selected.Value) || Color.Value = ColorDropDownBox.Selected.Value,
	IsBlank(SizeDropDownBox.Selected.Value) || IsEmpty(SizeDropDownBox.Selected.Value) || Size.Value = SizeDropDownBox.Selected.Value,
	IsBlank(Garment_Build_Dropdown.Selected.Value) || IsEmpty(Garment_Build_Dropdown.Selected.Value) || GarmentBuild.Value = Garment_Build_Dropdown.Selected.Value,
	IsBlank(Group_Dropdown.Selected.Value) || IsEmpty(Group_Dropdown.Selected.Value) || Group.Value = Group_Dropdown.Selected.Value,
	IsBlank(Mfg_Dropdown_1.Selected.Value) || IsEmpty(Mfg_Dropdown_1.Selected.Value) || 'Mfg column name'.Value = Mfg_Dropdown_1.Selected.Value
)

Use correct name of column in place of 'Mfg column name' in above formula (last line).

This should work if this column is single selection column in your SharePoint list.