Crypto investing is essentially zero-sum at this point. You will maximize expected returns on investment by being better informed, better connected, or better resourced than most of the other fish in the shark tank.

If you were better connected or better resourced, you probably wouldn't be posting here but using your connections or paying people to give you private advice. You can become better informed than you are now, but it will likely take at least a year to become better informed than average. There are enormous numbers of unavoidable risks in crypto investing, so even with the best possible information you should be prepared to lose everything you invest, and (if you try to leverage your investments for higher returns on things that seem like safe bets) be prepared for bankruptcy or worse.

If that sounds like a reasonable risk, go for it! Other people may have more specific advice on how to become better informed.

If you want exposure to crypto, I'd say: put a small fraction of your portfolio in the top coins on CoinMarketCap.com, and don't try to do anything fancier than that.

It seems like trading competently in crypto requires some degree of proficiency across multiple fields

I mean, that helps, but you don't need all of that to make money. Risk management, an edge, and, you know, a funded account, should suffice.

What mistakes have you made?

I made the mistake of selling most of the Bitcoins I was mining at $13 to pay electricity costs. They're worth like $60k now. Paper hands. Exit strategy matters. When you're tempted to sell, maybe buy insurance instead. I then made the mistake of trying to scalp trade Bitcoins on Mt. Gox. Not your keys, not your coins.

what should I be investing in at the moment?

Totally not financial advice, but I have a lot of Ether right now ;) Also, have you considered non-crypto investments? Diversification is helpful.

Can anyone suggest quality educational resources for getting started?

Start here. Not specific to crypto, and the presentation quality is disputed, but I stand by the principles.

Any other advice, hacks, and pro-tips that may occur to you would be very much appreciated as well.

Also research Nassim Taleb’s Barbell. It's a good approach for speculation.

If you just want to make long bets on the ecosystem and don’t want to learn too many arcane things, buy a few popular tokens on Coinbase and hope for highly volatile long term growth. Some of them will probably go to zero! Good luck, have fun, and assume you may lose all the money.

It seems like trading competently in crypto requires some degree of proficiency across multiple fields and practice areas: engineering, software development, data analysis, statistical modeling, cash flow assessment, insight into the psychology behind user behavior, an advanced understanding of economics, etc.

I think I want to dispute this. (Or at least point out that it doesn't seem obviously true.) It's reasonably easy to buy cryptocurrency (not trivial, but something you can figure out in a day). The hard part is knowing which currencies to buy (or whether to buy them at all, but you're starting from the premise that investing is a good idea). But you can just rely on advice for that. Unless skillful investing implies rapidly reacting to current trends, in which case you can't rely on advice and I take back everything I said.