The OVERWHELMING majority of daily quests are to play 20 or 30 spells within a specific color pair. There are only a few other possible quests beyond that, playing lands, playing creatures, attacking, and the dreaded killing opposing creatures (which is really hard to get in certain metas where opponents are rarely playing creatures or are protecting their creatures more aggressively, etc.). I would really appreciate getting daily quests that, at least occasionally, ask me to play a different way. Here are some ideas:

-Mill X cards (or have your opponent mill X cards)
-Cast X enchantment (or sorcery or instant or Planeswalker or artifact or even battle) spells
-Sacrifice X permanents
-Create X tokens
-Discard X cards
-Draw X cards (this should be a particularly large number)
-Gain X life
-Lose X life
-Deal X or more excess damage to opponents
-Play X creatures with flying (or trample or first strike or whatever abilities you'd like)

These are all things you can do pretty normally, just playing the game, but can also build around to make happen more consistently.
It would also be cool to have some goals that promote the most recent sets, like in Bloomburrow you could have had "Play X bats (or lizards or otters, etc.)" and in Duskmourne you could have "Unlock X rooms". I'm just really getting board of daily quests that don't actually feel like quests. I'd rather have more variety and even occasionally have to respin for a new one (which, likely makes you more money), than to have quests that are so generic and repetitive that there's no inspiration to try something creative, ever.

My final suggestion on quests (though this is just personal preference), is that you get rid of rewards for winning and change it to just playing. Right now, the "Play" areas feel just as competitive as the "Ranked" areas. The two feel nearly identical and you run into the same types of decks and rarely see anything particularly creative or unique. There's no reason to have rewards for winning in an area that's for casual play. Crank up the reweards for winning in the ranked areas and events, but just let playing games trigger rewards in the general app. This let's people feel the freedom to play how they want, competitively or casually. Prizes for winning go against the way Magic has most often been most popular. I don't know anyone that plays Magic that didn't fall in love with it by just playing the cards they had around a table with friends. Azorius Bird tribal versus a Rakdos good stuff (where the good stuff is defined by "cards I thought sounded cool when building this deck") versus mono blue stuff that lives in the ocean was a match I saw just last week from a group of beginning players. They had a blast and it reminded me of how I fell in love with the game and genuinely made me sad that Arena does not have a suitable environment for games like that.

Anyways, I hope these suggestions are helpful, and I hope they can lead to bringing more variety, creativity, and fun to the app. Thanks for considering!