My biggest concern wouldn't be the initial setup but rather the ongoing maintenance. A local junior dev would be even worse than DIY -- what happens when their code inevitably breaks?
Yeah, I've hired great, average, and lousy devs before (and been one) - I will keep my hiring on this project to people who like to make, serve, and talk beer.
Hope is that I can do the heavy lifting of getting things up and have something stable enough for me to run and a manager to be able to log in and see, at most.
I agree it's all about the customer experience whether it's as a wholesale supplier or craft event space.
In a small business I like having different networks for different things.
A few small stacks which are less likely to topple or do as much damage.
Somewhat like chemical processing, a few PC's might actually be "money-making machines" such as running a process-control app. These can be even more mission-critical than the highly secure office machines dedicated to accounting, or invoicing, or other financial work. If you have tech ability you will likely be better off mastering this hands-on before deciding whether or when to turn it over to an employee or contractor. OTOH an MBA without tech ability would probably be better off hiring an engieeer for process control from the beginning. You will probably want these PCs to never come anywhere near the internet. Highly amenable to physical security measures. Before you can rest, everything will need to be proven reliable around-the-clock without remote access over the long term anyway. This part should be just fine with a few miles of air gap theoretically, even if it's actually in the same bulding as the office machines. For this I also keep spare PC's of the proper vintage as well as pre-cloned HDDs and SSDs along with the spare mission-critial parts for the process equipment itself. No more trouble than it ever was.
About those office machines, to me these are the ones that replaced typewriters & copiers, calculators, spreadsheets and filing cabinets. Run-of-the-mill stuff where each typical user's desk has equivalent fundamental capablities. You still have to decide traditionally how you want to separate financial from non-financial desks, and different departments like Engineering and Customer Service, so I would at least end up with more than one net or subnet here.
Then there's the "internet machines". These are the ones that to an extent replaced snailmail, company libraries, faxes, phone calls, and in-person meetings. The communication lines which only ever really need to hold or handle a very small fraction of your entire data and perhaps only during the times you actually could designate for data exchange. This could reduce your exposure to electronic compromise quite a bit.
Each of these networks has dramatically different administration needs and I just don't think it's good enough to simply have two monitors on each desk, so I have at least two PC's, each with a monitor but only one with an internet connection and it really doesn't look that much different than anybody else. It's not like I have to purchase twice an many PC's for an entire skyscraper full of employees.
Traditionally, without secretarial services, if you gave someone a desk without both a phone and a typewriter, nobody ever expected that person to be as productive as possible.
It also makes sense to separate the different administrative needs, security considerations, and replacement & upgrade cycles from the begining in a way that they could be turned over to various trusted employees or organizations at different times as things evolve.
At some point for visitors I would have a completely different ISP for them alone.