Problem: Stretch custom blog feed to full width 5 thumbnails

Hey guys 👋

I would like to add a full width custom blog feed to my start page!

i have added the postcard layout but now there are two empty spots! if I add another line I doesn't look nice because it adds another 3 instead of just 2 ! I would need to add 5 lines in total to make it look good - that's too much to just showcase the latest blog posts . is this a bug ? because if I select only one line and stretch it to full width it should add two more thumbnails. can someone please help me ? is there a way to work around this without coding ? there should be a more flexible widget !