Cleanclean, another thought?
Do you use fabric softener? Fabric softener and some liquid detergents used improperly can get gunked up inside the holes of the agitator, under the wash plate, in the dispenser, etc. where you can not see it. I used to occasionally use fabric softener, and I quit doing it for that reason. The other reason is fabric softeners and dryer sheets coat clothing. This can make it more difficult for detergent and water to penetrate the fabric during the next wash cycle. I occasionally use scent boosters now and haven't noticed the issue return. Most of my washes are warm with an occasional hot. Water heater is set to the recommended 120.
I have switched to almost exclusively using Tide original or Tide with bleach powder (this has a really pleasant scent!). I'd probably use Persil Power pearls if they had them for a reasonable price in the USA. When I did or do use liquids, I prefer Persil intense fresh or Tide hygienic. A shot of Dawn dishwashing soap can help with heavier soiled items like those used to work on autos. For those gym clothes and stuff like that, vinegar instead of fabric softener seems to help.
For those clothes that seem to hold odor, I have to say my front load with the heated water "sani cycle" seemed to work better. Without bleach, that cycle on my LG would remove mildew, pet accidents, and gym/yardwork clothes odor better.