What to skip
Chlorine bleach weakens flax and yellows it in the sun later. Fabric softener coats the fiber, which is the opposite of why you bought linen. High heat sets wrinkles into cardboard and can shrink a set that was only lightly pre-washed.
Stains
Blot, do not scrub a hole into the weave. Treat with a little detergent and cold water before the load. Blood and wine want cold water first. Heat sets both.
Humidity and smell
If the room is muggy, the risk is not wrinkles. It is cloth that never quite dries. Smell usually means leftover moisture, often in the protector under the sheet. Wash smaller loads, finish the dry cycle, and keep a second set so you are not rushing a damp one back onto the bed. The humid-night note goes further.
How often
Weekly is a good default if you sleep hot or share the bed. Every other week is reasonable for a single sleeper in a dry room. Linen does not need to be washed into submission to get soft. It needs repeated gentle washes, not harsh ones.