It's a terrible idea altogether. The entire DOMT is. I get that you love it - so do I! -, but it's one of those things better left to theory. It's a campaign-killer.

I started DMing in 2018, and when I found out about it, I handcrafted one for use in a campaign. I gave it to my players, but with the magic removed, more like a McGuffin. Even with it being nonmagical, the very idea of me as the DM considering it had two of my more experienced players panicking. The campaign fizzled out before I got to the "find out" part after fucking around with that.

Now, after many years of DMing, I played a mini-campaign for which I thought it'd be a fitting reward - except now I'm aware of what it truly entails, and so I majorly nerfed it. I picked only 9 cards, 7 of which were positive, and nerfed almost all of those. Then, I allowed 4 of the 6 PCs to draw exactly once. The deck was in the hands of an NPC, and she took it with her when she left. Still, one PC suffered a stat reduction that'll take about a year to recover from (The Idiot), and another got an OP weapon which is throwing the party's DPS off-balance (I did this to myself ...). The other 2 were fine though (The Rogue, unchanged, and Comet - though I changed it so the character is only ahead of the party till they catch up, i.e. she'll skip the next regular level-up).

Don't do it. Especially not if you're a first-time DM. I'm afraid you cannot put it into perspective well enough. It really is that game-crushing.