For $4k, you'll be able to get a fantastic grinder & machine. It will simply come down to personal preference for different features. You really should do at least two things, 1) familiarize yourself with the types of machineshere
. 2)Start reading reviews
on this site.
Depending on your needs/desires and the fact that you only make espresso, it may be as simple as a Quick Mill Alexia
with PID control which is arguably regarded as one of the best espresso only machines. And a great grinder like a Mazzer Super Jolly
. But no matter what you do grinder first, grinder first, grinder first! Don't skimp there.
Edit: But if you're ever going to steam, even for guests then look to an HX or DB over a single boiler like Alexia.
Living the caffeinated life.