The best tools and equipment to digitize film negatives with DSLR, without breaking the bank

I am considering buying Lomography DigitaLIZA film masks for 35 mm and 120 mm films to use within my digitization process, however, I am not sure what the best methods are for the other areas of my process.

I fight mainly for the backlight of the negatives. I have an iPad that I used initially, showing a blank screen with the negative of the film on top and a sheet of glass / plexiglass on top to flatten it. However, I discovered that by inspecting the photos of my negatives, I could actually see the Retina display pixels in the whitest areas. I obtained better results without pixels in the background when lifting the negatives, moving them away from the screen and supporting the configuration on, for example, a cardboard box, however, this can lead to another problem … Make sure everything is level.

I have seen people use copy stands and light panels to watch movies, but so the products that I have seen can start to incur a great cost.

Does anyone have similar experience with digitizing film negatives and a way to do it without breaking the bank?