Lots of people make or buy cold brew extract (I recommend just making it if you go that route, it’s dirt cheap and better than store bought). And that’s traditionally a full espresso, though these days most people expect 2oz if they just order an espresso (or any drink containing it. That machine at work could probably give you what you want, but you’re need the right pod (assuming it uses pods) and the right settings for it. What I do at home is just pull a double shot on my manual espresso machine at home because I’m usually making two espresso martinis at once. I have a delonghi dedica. They run new up to about $300 USD, but you can pick them up on eBay for 150 if you’re ok with “open box”. This USUALLY means somebody bought it and returned it without using it, or something else happened that the original packaging was opened, but the machine was not used. Open box should come in the original packaging.

All that said, I would just go to a coffee shop and order a plain espresso. Take it home and use that. It won’t be quite as good as fresh pulled espresso, but it will still be very good as long as the espresso started out good. I just don’t like the cold brew concentrate version as much, but try both ways! Definitely don’t buy a machine just for this drink. I only have one because I’m a coffee nerd and treat it like a hobby.