I’ve been using this device https://www.amazon.com.au/gp/product/B01GHKL7HQ/ref=ppxyodtbasintitleo01_s00?ie=UTF8&psc=1 to scan & save Dad’s slide collection, or at least those of which I don’t already have copies. It’s really effective with the thicker plastic-framed transparencies because one of the feed-in attachments is a quick change magazine that can take up to 12 slides in its hopper. That attachment is useless with the thin cardboard-framed slides, they get jammed in the mechanism. For those there is a hinged frame that holds four slides at a time and you manually insert that into the slot in the side. There are indentations to enable accurate placement of the images to be copied. You can select between 5 MP & 10 MP jpgs which are stored on an SD card.
Very fast & effective with slides.