First, I switched the hot and cold water inputs. My machine's idea of "warm" was actually more like "very very cold". Now, it gets enough heat. I also cranked up my water heater as high as it would go. These two changes effectively take care of all mildew issues. Don't listen to all of the horrible water temperature advice out there; they advocate for temps that optimize for bacterial growth. Hotter is better.
Second, I looked up videos on youtube to figure out how to make it use a lot more water. This is a relatively simple process that involved unscrewing and removing the case, using a hair dryer for 30 seconds to warm up a loctite covered screw, and turning that scree about a quarter turn. More water is always better.
Third, I ordered a giant sack of Sodium Tripolyphosphate (STPP) from a chemical supplier. Prior to that, I used to buy Trisodium Phosphate (TSP) from Amazon (make sure you get the real stuff). Both require hot water, need about a tablespoon per load, and work extremely well, though STPP is supposed to be better (I haven't noticed a difference). This has two big impacts. Your clothes, especially towels, will feel much softer and nicer. And also, your clothes will stop smelling "good", because STPP is a rinsing agent that helps get all of the soap out of your clothes. The only reason your clothes smell "good" is because modern detergents do a terrible job and the perfumes are added to cover the odor.
If you want to enter a time machine back to a magical era when appliances worked correctly, add a tablespoon of TSP to your dishwasher and run it on the hottest setting.
I also tend to empty it within an hour after it's finished so I have no problem with mouldy clothes or linen. I hang out all of my washing and live in Australia, though, so that may be different since it's permanently a million degrees here and everything dries quite quickly.
I'm very happy with my front-loader. My only worry was that the cycle times were longer when I go 'oh shit, I need this clean and dry in an hour' but it has a 30 min quick wash anyway and then i can toss it in the dryer or hang it out in the sun if it's a hot day. It's served me well.
edit: I also wash all clothes on the 'cold' setting aka what's straight out of the tap. Linen I'll let do at the 40 or 60 or whatever it wants to do it at because it seems to produce marginally softer results but I don't really care either way and prefer to save the electricity on my clothes washes which make up the overwhelming majority of my use.
We had issues with mildew-smelling towels in our top-loader once during the rainy season (one month of non-stop rain and we hang-dry our clothes) but changing detergents solved that.
I hate all our appliances. Every last one of them. From the microwave that lasted a year to the freezer that leaks water and ruined my hardwood floors.
They're all garbage. Horrible, horrible expensive garbage.