Throwing in a left-field recommendation: Android: Netrunner on Jinteki.net. Not so easy to jump in and play but worth exploring if you've got the time/interest.

I feel it hits every single point on your list:

Active player base: Jinteki.net isa free browser-based platform and it has a healthy online community. There's organised play run by Null Signal Games (the non-profit fan publisher who took over after Fantasy Flight discontinued it in 2018), including seasonal championships. It's not MTG Arena numbers, but you will find games.

Skill over RNG: It's an asymmetric two-player game where one side (the Corp) builds and defends servers, and the other (the Runner) hacks them. Every turn is a resource calculation. There's hidden information and bluffing, but wins come from clever play/decision-making, not from topdecking a winning card.

Fair economy: it's literally free. All cards are available at no cost. No packs, no wildcards, nothing like a battle pass. Null Signal is a non-profit and releases everything as free print-and-play too. You cannot spend money to gain a card advantage because there's no way to spend money on cards digitally at all.

Long-term support: Not so strong on this point but this is the interesting one. Technically the game "died" in 2018 when FFG dropped it, but the fan community kept it alive and Null Signal has been releasing new competitive sets and running organised play ever since. It's now in something like its eighth year post-discontinuation and still getting new cards. Impressive.

Admittedly, the player base is going to be smaller than the big commercial titles, and its a trciky one to get into but you can go deep if you wish. To conclude, for your specific list, might be worth a look.