Do I need to save more/ invest more?

26y/o making 75,000 USD
100 dollar monthly HSA contribution with 40 dollar employer match
5% 401k contribution 2.5% employer match
No debt
746 credit score with 3 cards 10k 10k 3k credit limits, always pay my balances end of month
Car paid off
Rent was 1400 for 14 months but now down to 800 starting this month

I have worked this job for a year, first raise was at 6 months 73.5k to current. Fresh out of school starting at $0 saved essentially

I have 14k in my checking account and 5.5k in 401k

My company offers a share purchase plan that i feel I should take advantage of but dont know how aggressively to use it. Pretty standard 15% share discount with no limitations on withdrawals. Maybe i should pump some of the money saved on rent into this?

Pretty much know nothing about making personal investments and if that’s something i need to start now outside of what ive already listed.

wanting to upgrade my office/ pc setup. 2-3k on that doesn’t sound scary to me as its my main hobby and i spend almost all of my time there working or gaming. Not sure if that’s reasonable or not given my current financial situation.

Main points being should i use the SPP more, am I spending too much, and should i start my own investments outside of work.