I have tried things similar to scanning slides on a flat bed scanner. I found two significant problems.
It was impossible to clear the scanning field of dust. So the resulting images, when enlarged, were of poor quality. Every speck was enlarged at least 7X in any print of the slide;.
The resolution of the flat bed scanner, i.e., pixels per inch, was too low to produce images suitable for anything.
My decision was to use a service. A service has the experience, know - how, and equipment to give me a usable result.
A service costs a few bucks, but much less than a scanner.