You are in great shape - simply asking yourself these questions at age 23 is going to set you up very well. This is what I would do in your situation in the near term:
1) Get a credit card - set it to pay in full each month and build your credit. Properly using a credit card is very beneficial and gives you much more fraud protection than a debit card. Do not get a credit card if you don't set up automatic full balance payment. People who hate on credit cards are usually people who don't have the self-discipline to use them properly.
2) Decide what level of emergency fund is right for you - Don't fret the 0.01% interest for your emergency fund, but once you've hit your goal, start putting money into:
3) Max a ROTH IRA - This will be financially optimal for you given your current income - you're not paying much in taxes so tax-deferred accounts don't give you the bang for your buck that a ROTH will.
4) Increase your 401(k) contribution - Setting the 4% to get your company match is an excellent top priority. If you get all the above going, then I'd keep working on bumping yourself up beyond the 4%.
That would by my general priority list of things to do. For investing, I recommend getting Vanguard or Fidelity (I use Fidelity, but Vanguard is the consensus on this forum, which is fine). Stop picking stocks and find a good portfolio of large, mid, small cap ETFs, a bond fund, and a few international funds. Keep it simple and keep it balanced. I personally roll with: IVV(40%), IJH(15%), IJR(15%), IEFA(10%), IEMG(10%), AGG(10%). I tell you that as 1 data point - you will have many, many other very good recommendations from people on this forum. Take them all with a grain of salt and research them yourself, but I figured I'd give you a good starting point, which is the portfolio I've landed on after ~12 years of investing.
The last major piece I'd focus on is continuing to develop your professional skills and keeping your eyes peeled for more lucrative positions, both financially, and in terms of enjoyment/work-life balance. The highest paying job I've ever had was also the most fun, least stressful, and highest reward. Maintaining a solid spending plan and not succumbing to "lifestyle inflation" is critical. But, also remember that there is a limit on how much you can trim from your budget, but no limit on your earnings.
Good luck and keep asking questions on this forum. The people here are amazing!