Sometime in the last century I thought I needed a single-lens reflex (SLR) camera with a macro lens and fancy lighting to take good pictures of electronics. This did work well, especially with my Canon Rebel 35mm camera mounted on a tripod with a remote shutter release cable attached to the camera. Image blur for this type of photography is almost entirely caused by camera motion, rather than object motion, hand-held objects being an exception. Don't hold in your hand what you are trying to photograph.
Then along came digital cameras, including an "upgrade" for my Canon Rebel, but I couldn't afford that. So I had to take pictures on 35mm film and wait for the film to be processed. Using Kodak Ektachrome meant I could get this done at a local drug store with just a few hours delay. Getting the results digitized, either from a print or from the color negative, added more time. Finally, the image had to be edited to fit the upload constraints of whatever blog, forum, or whatever I was posting to.
My first digital camera was a pocket-sized Panasonic with telephoto and macro lens capability. It created JPEG formatted images that I could import into Microsoft Paint (through a USB port) to resize, crop, and edit to make suitable for uploading.
I bought two of these little cameras, one for me and one for my wife, before eventually upgrading to a cell phone that took pictures. Using my home WiFi network, the images saved on the cell phone could be easily copied to our personal computers on the network. As the years rolled by, we kept apace with newer cell phones, eventually abandoning Samsung Galaxy phones for Apple iPhones. No particularly good reason for this, other than the fact that wife likes and uses Apple products. One thing I noticed was the quality of the cell phone cameras kept improving with each new generation. The cell phone images now rival what can be obtained with uber expensive DSLR (Digital Single Lens Reflex) cameras. They still remain more or less useless for viewing images on their LCD screens in bright ambient daylight though.
If you are having trouble taking good images with high contrast and depth of field, consider a visit to a used camera equipment dealer, also known here in the States as Pawn Shops. Be sure to try before you buy, and don't try to buy the latest model. Do some research on the Internet to find out what the going price is for what you want to buy. Don't be afraid to make the shop owner a lower offer than their asking price, your offer being a few percent more than what you can purchase on the Internet if the asking price is more than that. Buying from a real person you can complain to (even if there is a sign saying ALL SALES FINAL) if the camera fails, will sometimes elicit a replacement offer even if you can't get a cash refund. Cash refunds from Internet sellers can sometimes be very difficult to obtain. Cash refunds from Pawn Shops are unheard of without a written, signed, witnessed and notarized, iron-clad guarantee, which no pawn shop I have ever heard of will issue.
Good luck taking better pictures for this forum. Don't expect a Pulitzer Prize nomination though.
Meanwhile, visit this Ali Baba website
for a plethora of onion-shaped aroma diffusers, most of them based on ultrasonic transducers, and virtually all selling for less then twenty bux plus shipping. You might find an exact duplicate for your sister's diffuser. If so, buy it and present it to her as if you had "fixed" her old one. Maybe add a few "distress" tool marks to make the substitute more convincing. Or just swap the external case if that seems feasible. Good luck with your "repair."