Some Issues

If you give someone 5 mins they will use that as their strategy of time wasting in hoping the other player will quite/surrender. I can only hope once you pick your team you are not stuck waiting 5 mins for someone to afk till they decided to select the cards they were going to anyways. That you are able to move on to another match and I guess if you want to see the results you check in after the fight.

I see what you are trying to do and I respect that. I just fear people will create bot/automation to data mine/ check the battlechain and then use external information to their advantage in what cards you have. At least you are going to show the last few matches.

In games like healthstone, you had players waiting out their timer every single move. Not because they do not know how to play the game or because they were having issues picking a card to play. It was done so people who want to play fast leave the match getting them an easy win.

I also have concerns here about not all splinters being available. While before it had not happened yet with conflicts. If it did you just would not play for those 48 hours since you did not have a great team/that splinter.

If you surrender are you taking a reduced amount of loss or does it consider it like losing a game?

Possible Solution?

I think it is great to know what splinter you were facing. That gives the player some insight into what they could be facing along with the mana cap and rules of combat. You can guess a lot just based on that once you understand the game and what possible monsters that person could present. This would also allow people to play what splinters they do have.

Timers

If a card is gifted or sold on the market then it must have a period of 7 days where it does not get played in ranked battles.

You do take a cut from sales right? That should be enough of a deterrent from people trying abuse high level cards that cost a fair amount. If they want risk putting their high level cards up for sale to buy them on an alt they also risk someone buying it before they are able to. So I’m not sure why buying cards off the market should have a cooldown before you can even use them. That be like me going to the store to buy milk and being told I’m not allowed to drink that milk for 7 days. By then I may no longer be interested in drinking milk. A lot can change in a game like this in 7 days where someone may no longer want use that card.

While I do like the idea of a cooldown on gifted cards. I think if you are gifted a card you should still be able to play it but it should have a cooldown preventing it from being gifted again. It should be either till the end of season or 7 days whatever one is longer. That way they can still play if they won a card/someone is helping them out. While also reducing “abuse” to at least some degree.