My computer people - So my hard drive is going bad

The most important thing is, Back up your data NOW. Back it up before the hard drive has totally failed. What kind of computer is it, what brand model, etc? I work in IT and did break/fix for years. There are many computers that the hard drive is soldered onto the motherboard. Based on your description the iMac comes to mind, but of course, Apple is not the only manufacturer soldering on SSDs and Memory. You might be able to find someone able to do the repairs, but you also have to consider repair price vs a new computer. Really calling it soldered on is not the most accurate description. It's more "integrated" than soldered on. Before someone comes and talks about planned obsolescence, there are legitimate engineering benefits to integrating components into the motherboard.

I did some research and found a detailed instructional video for your hard drive problem

Not believing this

I think maybe he's just not particularly skilled with dealing with AIOs and doesn't want to risk damaging it. I can't fault him for that. I would look for a different shop that maybe has experience with them.

Can you add a card in PCIE or any other way?
What kind of computer is it?

Is your computer ike 2 in 1? Computer behind monitor screen? If that guy can't open it to replace hard drive then take it elsewhere

This is a typical performance issue since components need to fit together in a sometimes difficult way. For example there are graphic cards which might perform up to date, but are too big to fit into the rest.

I for myself still struggle with even attempting to take my tower monitor to just any repair guy since it's too big and sorta too loose with its components. Do you really need a tower PC for work? And what's the actual issue with the hard drive?

How old is this computer?

Check for screws at the back and the bottom. If they're there, it can be taken apart.

"isn't built to be replaced" lmao wow

Some bad designs have it on a side of the motherboard that you have to disassemble the whole computer, usually business models like Dell Vostro, but if a computer guy can't disassemble your computer you took it to the wrong person for sure

The pain in the ass ones usually take me around 30 minutes (some good designs take me 3 minutes)

Do you have the model number?

I"ve repaired those all in one PCs before. They are a pain in the ass but it can be done. The entire back of the "monitor" section has to be removed to get to the drive. Find a better repair guy.