power bi scatter plot with customized color points and cross-filtering cards

Question

I created two dim tables Price and Km and made a one to many relationship with each of FactTAB1 and FactTAB2

1. I've not found on the web and in the sw setting the possibility to show color of the points in a scatterplot with axis Price and Km based on the entry being from FactTAB1 or FactTAB2 (it requires a always a field). I understand I could join the 2 TABs and add a column to use as legend with values the name of the Tab of that entry but there are solutions less memory intensive than duplicating all the data?

2. If I select a datapoint in the plot it will only change the card related to km and price, but not the other (Brand/Model/etc) even if I have created dim tables with 1:many relationship even for those dimensions. I understand it is filtering only the two dims putted on the axis but there is any way to make it filter also the other dims. At the moment i can only reproduce that behaviour with the top-right multirows card but can't control too much the appearance, it's just a workaround but would learn a better way to make this work with single cards.

3. I've made a Photo dim table with this DAX code Foto = DISTINCT (UNION (SELECTCOLUMNS (autoscout24Data,"Foto",autoscout24Data[Foto]),SELECTCOLUMNS ('automobile-itData',"Foto",'automobile-itData'[Foto]))). It should select the unique values from the two Fact Tables and it shows me no duplicate, but when I try to build the relationship between this new dim table and the two Fact Tables it doesn't allow me a 1:many relationship and can't understand why. At all.

Thanks in advance

I tried many workaround and google search and sw settings alternative. But not find a fix to these 3 problems. Cross filtering between two facts and common dimension tables in Power BI Desktop this seems related (cross-filtering) but more 'elementary', I've already two dims cross-filtering two tables but can't make the plot cross-filter even the for the other dims. I've tried to create measures with SELECTEDVALUE Dax code but hasn't fixed in my case when I put those measures on the single cards (except for Km and Price).