If you are at all serious and, looking at this at the extremes, consider coffee as a gourmet food as opposed to a morning drug addiction, the priority has to be the ability to make the best coffee possible for the least amount of money.
That amount of money is relative to your total available funds. It might be that two flat rocks and a clean gym sock are a luxury, or it may mean that, without a second thought, you buy a LM two group GB5 for $13,500 and a LM GS3 for about $7,000 and then decide which you like and sell the other used.
While not espresso, and taking for granted a source for quality, freshly-roasted coffee beans, then my recommendations for a starter package are:
1 - a good grinder (a Baratza refurb is hard to beat for the price)
2 - either (based on budget):
a. 1st choice an Espro Press
b. 2nd choice an Aeropress
3 - A scale that weighs in 0.1 gram increments
4 - A way to measure water temperature
A setup like that has great potential to (relatively speaking) easily make excellent coffee. From there the choices are virtually limitless.