Can rostering a few 5 
's ruin your pvp scaling? The first three nodes of any pvp event are easily beatable for me. After that I get matched against champed teams that I don’t stand a chance against. Any insight would be helpful.
It depends on where your roster is at. If you are established in the 3-star tier (meaning you no longer rely on your 2-stars for wins) rostering 5-star covers shouldn’t have much effect. While still in the 2-star tier it isn’t advisable.
If you start leveling them, that will have an impact regardless of your roster, on both pvp and pve.