Got the game early, went inactive for two years or so, came back to arena packed with R7 squads

Squad arena is just a small part of the game, I'm REALLY liking the galactic conquest or whatsitcalled mode because I can actually squeeze some decent gameplay out of it, plus I like all my characters that I've upped - starting over will feel a bit mean to this acc just to get a better arena shard, but thanks for the info