Filter a gallery based on a lookup column in Sharepoint which allows multiple values

[RalfsZ]

Hello,

Currently in the process of creating an app which users would use to work on submitted items instead of a Sharepoint list.

The Sharepoint list contains couple of columns, text, attachments, person, etc. 
One of the columns is a lookup column which takes the data from another SP list - the column also allows multiple selections.

The issue here is I can't think of a way to filter out the gallery based on the lookup column, which as so happens, is the column users would want to filter by most - Projects.

I've made my way to at least show the list item projects in gallery label by using (as it does not offer the value by default):

Concat(ThisItem.'Project', ThisRecord.Value &";
")

Which gives me in the label (where there are multiple items):

Project1;
Project2;
Project3;

Now, the gallery is pre-filtered already, so the project filter can't be the only one (I am using StartsWith, because the list will get over 5K at near future).
There will be more filters to come, but they are simple to make, the problem is the Projects column.

Filter(
    'Srource',
    StartsWith(AppStatus, "AppNew"),
    IsBlank(CR_PersonFilter.Selected.DisplayName) || Purchaser.DisplayName = CR_PersonFilter.Selected.DisplayName    
)

I've tried adding an input box and tried to put it in a search function in the filter query with no luck, as the search function, at least as much as I understand, does not want to interact with a gallery but only with sources.

What are my options here? 
Are there ways to split out the Project column values to multiple labels, maybe? 


Thanks!

[Drrickryp · Accepted solution]

@RalfsZ 

I think the solution to your question can be found in @RezaDorrani 's video here:  https://www.youtube.com/watch?v=44j2VRbdWjk 

[RalfsZ]

Thank you, the video you have posted helped me to make it work.

I did the same things as @RezaDorrani showed, albeit with small differences in source syntax, but now it works just as I've wanted it to. Can't believe I did not come up with a find on his video from my google searches 🙂

Thank you for pointing me to the correct direction, and @RezaDorrani for the workaround!