Suggestion: There should be a Casual play option where we can add some "home" rules to create and play with friends online
Similar to the Play option, there should be a Casual option that can be selected as a format which is non-competitive and not for people to try out their ranked decks like in normal play and it is completely just to have fun (you could even make it not count for daily missions or xp), the creator of the game should have control over a few things such as starting life, and from which sets cards in that game are allowed to be played. Also allowing a 2-headed giant format would be AWESOME, but I'm sure that would be an entirely separate endeavor in and of itself.
Having a completely casual and fun format such as I have proposed could help maintain players that sometimes just want to play and have fun without the feeling that they must play a highly competitive deck just to have any chance at winning a game. Plus with no reward beyond just the simple fun and enjoyment from playing it disincentivizes and can even stop most players from joining that are solely playing because they want to win with the combination of no return for their time other than playing the game as well as potential constraints that would restrict how those players could play.
I am sure we would see players that love the game setting up groups on discord creating casual play groups to set up something like an FNM in the old days where there were not prizes other than randomly a fun participation special card and that most people at least at my LGS became friends and would regularly play because no one was trying to dominate the games just simply have a reasonably fun time enjoying the game itself.
Please consider this as I talk with many players of MtG both on Arena and irl they all seem to share the same sentiment as myself that sometimes the overly competitive players ruin the game in a very bad way that deters some of your loyal players like myself and others from playing on the regular anymore. Thanks, Have a Great Day!