Trading

I don't think trading and crafting can work together, and crafting is much healthier for the digital format of the game IME. PTCGO is completely impossible for me to play and have fun because I need to spend a bunch of money on pack codes to trade for cards to play with newer cards and with a coherent deck. In PTCGL I just need to complete the daily challenges for the battle pass and use excess crystals on smaller sets to eventually start getting credits instead of cards from them. I can spend money if I want to, but I don't have to because grinding doesn't even get you the cards you need.

If you want to trade cards, you've got the paper game to do that, which very much is the actual TCG product. The digital clients have always been a marketing tool to introduce people to the game to get them collecting and playing the paper products (that just so happened to be really convenient to substitute for paper play while it was impossible for the past couple of years) and are not intended to supplant the paper cards entirely. I think the crafting system is superior for that goal than having a trading system. The closest I could see to trading is being able to break down cards into credits.

I personally very much don't want to have to deal with another player-run economy like PTCGO that makes it impossible to play for free or with minimal investment.

"Trading card game" is just a phrase for the type of game it is. You don't trade cards during the game.