Judging by the size of the dust threads, these are negative scans, and according to the EXIF info they're done with a Fuji Frontier SP-3000 minilab scanner.
At first glance the grain is quite terrible and also looks smeared. I suspect an incorrectly configured scanner - perhaps infrared dust removal was switched on, or excessive grain smoothing was applied.
If you can, try to do some scans yourself with dust removal, grain removal & sharpening switched off, and see if you get better results. (Or even better, optical prints, if you have access to a darkroom.) 100 & 400 ISO films should be capable of better than this.
If photo 3 is the first shot on a roll, it could simply be fogging from when you inserted the film.