I've seen a lot of people posting asking how to beat the Meditating Mage Spam deck, so I'd like to share my experience against them and how I've managed to consistently defeat them with a wide variety of decks, including Devotion decks with no offensive purify. Obviously if you have offensive purify and a lot of control tools in round 1 to answer Defender, Idarran and Meditating Mages (MMs), the matchup is a lot easier, but there is another successful strategy that doesn't depend on you drawing your exact answers in r1.
The strategy is to win round 1, drypass round 2, and overcome their carryover in a medium to long r3. The most dangerous thing about the Meditating Mage deck is that in round 2, they start with a bunch of MMs that have patience going, and they can play Aretuza Adepts for 5+ engine points per turn. If you win r1 and immediately pass r2, you don't have to deal with these mini-Kolgrims in r3 because those carryover mages won't have Patience active in r3. Also, a big upside of this is that even though you drypass r2 and they have carryover, they need to play at least one card in r2 anyways in order to click on their Meditating Mages to activate their Resilience again to bring them to r3. They will still have a lot of carryover at the start of r3, often something like 20-40 carryover depending on how much removal you had in r1. But they will have pretty much no good plays left in r3 and be playing like 4-5 points per card. Most good decks can overcome that in a medium to long round and with a little bit of Card Advantage. We can get this card advantage by utilizing a Hero Pass in round 1.
Here's how: Play a very deep round 1 even if you can't answer the MMs. Their deck has very few points in round 1 because they don't start with any carryover, and are busy playing a ton of meditating mages that end up being 5 or 6 points in r1. So when it starts getting close to the end of the first round, you should have a very big lead (20+ points). You can usually consider hero-passing r1 when your opponent has 1 or 2 cards left in hand. A Hero Pass is where you pass and win the round even though your opponent hasn't passed yet. It's used in a situation where you are so far ahead that you believe your opponent has no way to make up the point gap with their remaining cards in hand. Remember, their deck MUST play a Tissaia in r1 before they can pass. Otherwise, they don't get the carryover to r3. So if they have only 1 card left in hand in r1, it has to be Tissaia, and the amount of points they will get is 6 + 1 vitality on every MM, plus 2 points per leader charge remaining. So if they have 5 MMs on the board, you can hero pass on their last card if you have a bigger lead than 13 points. It gets a lot trickier if you want to hero pass on their last 2 cards. Because now, if they play Tissaia first, they will get 6 + 2 vitality on most of their MMs, and their second card could potentially be a Voymir or a Dethmold. If they had the same 5 MMs on board, in order to Hero Pass a Tissaia + Voymir, you would need to have a lead of more than 6 + 10 + 10 = 26 points.
Successfully pulling off a Hero Pass is an amazing feeling, and will mean that you actually get to WIN the round on even cards or with card advantage. Then you gain another card from drypassing r2 because they have to play one card to click on their MMs, and you'll have perhaps 2+ card advantage in a r3 where you get to play 7 or 8 cards, so a fairly long round for you to develop engines and synergies.
In the round 1 mulligans, you'll want to try to get a hand that is strong but mostly playable (except for maybe 1 card) and has a lot of engines because this is going to be the longest round. Removal is great even if you can't get past defender because they will have to play MMs in the other row at some point.
Here are some examples of me playing versus Meditating Mages with a few different decks, and you can catch me streaming live every weekday starting around 7pm CEST at
Devotion ST Symbiosis vs Meditating Mages
SK Rain vs Meditating Mages (Opponent even double squirrels me):
Devotion NR vs Meditating Mages
I hope this helps people understand the matchup better and good luck out there on the ladder!