Why separate laundry? I've tried it in the past, but don't do it anymore. Same result. The stains that can be cleaned get cleaned. The stains that would persist, persist. The only difference is the temperature setting.

As for separating colors - in my life I've had a piece of clothing stain other clothes 2 or 3 times. Once I put some white shirts and they came out pink because of another red shirt. Funny thing is, the pink was very uniform, so it looked as if the shirts were originally pink.

If my washing machine breaks, I'll get a second hand one. If I get a brand new washing machine, it will have to have a manual mode where I can set the desired program manually. For example, what is "towel setting"? If I can't see and modify the setting (e.g., A temperature for B minutes at C RPM, then D temp for E min for F RPM, etc.), I wouldn't use it.

Colors don't bleed much these days. Some might, e.g. on handmade clothing such as tyedye but most commercial colors don't.

If you wash items of different weights, fabrics, etc. together the load can get unbalanced more easily. Such as as single heavy towel or jacket in with a bunch of light synthetic items.

The "towels" setting uses warmer water and faster spin speed but an overall shorter cycle (at least on my washer) compared to the "normal" cycle. This probably presumes that towels usually are made of cotton and aren't very dirty.

I agree that a fully manual mode would be nice. My washer (LG) doesn't have that but by knowing what the various cycles and optional settings (e.g. soil level, extra rinse) do you can get pretty close to what you want.

Consider getting a European model..

I was always confused doing laundry in the US. Warm cycle or cold cycle?

I have 30C, 40C and 60C depending on what I'm washing. I probably have more programs, but never use them. For pillows and stuff I adjust spinning, from 1200 to 400 RPM. And I use special short, low rpm handwash program for wool.

(Side loaded ofcourse, that way the dryer can be on top)

It depends. My clothing doesn't (typically) need to tumble for long whereas towels might and bedding needs to go for much longer. In general it's probably better for fabric to be washed for less time if possible. It wears out.

Also if you pay close attention you'll notice that things don't come fully clean (old machines didn't either) just "clean enough". Throw some well used dog bedding in with your shirts and this fact might become more readily noticable. So it makes sense to wash like-use with like-use for that reason alone.