Do not iron.

Block it. That is, dampen it then pin it out to its proper shape and size on a flat surface, and let it dry.

I always use a warm iron and a damp tea cloth.

I used the blocking with a damp cloth method on a cardigan I knitted for GS, and it does work. I would try and avoid applying heat. As for shrinking sweaters - ruined one expensive one recently ?‍♀️.

I would pin it out to shape and use a steam iron without letting the weight of the iron rest on the garment. Hold the iron just above it briefly. If you press down, the knitting will get squashed flat and flattened. The steam without the pressure makes it look neater without the flattening. Don't overdo it, or you will never get back the original springiness.

Having ironed a nice knitted hooded jacket I made for GD and spoilt it, wouldn’t do again. Used damp cloth but iron was probably a bit too hot. Try the blocking.

This site tells you to soak the item, roll in a towel to remove excess moisture then block:
kelbournewoolens.com/blog/2015/4/tips-tricks-blocking-your-knits

I think I read about it first in a knitting book, can't remember where.

Good question silverlining
I could try that with my nice but shrunken cashmere jumper.

Sometimes I've blocked out the pieces of knitting before sewing them together.

I have never heard of blocking jalima. Can it unshrink woollen items?

sorry, wasn't giving orders
It is just a suggestion

Block it!!

Home-knitted garments look so much better when they've been blocked. Pin it out on a blocking board (you can make one from a piece of insulating foam, an old cot mattress, covered with old sheeting.
Then pin the garment on to it, shaping it nicely.
Cover with wet tea towels and leave to dry.
Or damp the garment first before you pin it out.

It does make an enormous difference.
Some sites recommend using a steam iron over a damp tea towel and pressing lightly, but I think that blocking and allowing it to dry naturally is much better.

I sometimes use a gentle heat from a hairdryer.

I would probably try it in the tumble dryer with a damp cloth in beside it. Check it every few minutes to see it is all right.

Or maybe put on a hanger and hang near the shower.

and avoid the rib.

I would iron, carefully. Warm iron, damp teatowel