Just thought I’d answer your query about the difference between converting to & assigning a profile.
There is definitely a huge & extremely important difference between the two operations. When converting, the actual pixel values (RGB, CMYK, etc) are altered so that the visual appearance of the image does not change too much. So if you have an image in anyRGB and convert to a printer profile, ideally the image won’t change its appearance much (lets say the image is completely within the gamut of the printer profile you’re converting to, and you convert using relative colorimetric). If the image had a pixel with RGB values of 100r146g69b, it might end up being 88r179g54b (for example) once converted to the printer profile.
When a profile is assigned to an image, what you are actually doing is changing how you define your color space. An easy way to picture this is to think of the difference between Adobe RGB and ProPhoto RGB - the RGB primaries in ProPhoto are much more saturated than those of Adobe RGB. But, here’s the difference from converting, the pixel values themselves are not altered whatsoever when assigning. No RGB values are changed. It is just the actual definition of what shade/tone/chroma/hue you want for your red, green & blue primaries, which is why if you go to assign a profile is Photoshop & scroll through the list you will find your image getting some wild color changes when you get to some of the rarely used profiles, like some of the scanner or camera profiles.
An easy way to remember the difference is that assigning a profile keeps the (RGB/CMYK/etc) pixel values but changes the image’s appearance. Converting to a profile keeps the image’s appearance (as much as is possible) but changes the pixel values.
Hope that’s not too confusing.