For single-dosing (espresso) I recommend a conical burr (more forgiving and easy to dial in) grinder with infinite grind size setting. Consider those (just in that order): Niche Zero, Bezzera BB005, QuickMILL 060 EVO. Also, the following models can be considered (they are cheaper, but have smaller, 38 mm, burrs): Ascaso i2, Lelit Micro Metric Fred, La Forza F19MM, GRAEF CM 702, Isomac. Unfortunately, Baratza Sette 270 not in the list because it's too loud and prone to breakage (if these are not problems for you, then 270 is very a very good choice).

I second the experience with Baratza problems. My Sette 270w stripped its plastic gears about 2 months out of warranty. To be fair, I understand they're great on the customer service side. I'll have that experience soon after the holidays.

I also agree that you should keep your Capresso grinder. I had one for years that was great. Then you can add a dedicated espresso grinder that will do a better job, especially on a budget.

Not on the subject of grinders, but perhaps on the more base subject of your coffee journey: Have you considered an Aeropress? It's really cheap at $30 and will get you a whole new flavor of coffee. You can keep using your Capresso grinder for a new kind of coffee while you investigate espresso options.

A final thought: Don't under estimate the importance of an espresso grinder on the flavor of the coffee. A couple of years ago I got my first nice espresso machine and thought I could get by for awhile with the Sette, but I always felt like I'd settled. I'm now looking at spending more on a grinder than I did the espresso machine. Not that you have to spend a ton, just don't under estimate it's importance, that's all.

Good luck!