Is it a good idea to exclude competitor names, or should I write a search ad that says our brand is better than XYZ competitor and show differentiating factors and benefits that make us better?

I just launched my first pmax campaign following the course. However I added in multiple countries where we have gotten sales in the past, instead of just targeting US only. Is this recommended or is it better to create multiple pmax campaigns all targeting one country individually? (I feel that would cause disorganization since i lean heavy on the "account consolidation" rule.)

I noticed merchant center also has attribution models in the conversions settings. Its set to last click. Do I change it to data driven? Just like how we set it to data driven on our google ads campaigns?