One thing you can do is stop buying clothes with nylon and polyester (which is hard to find but not impossible) since these release plastic particles when you wash them which eventually enters the sea and the food chain.
Furthermore, I kinda think that this must be solved on a political level. It’s good if more and more people ask for plastic-free products, but don’t think that this changes anything on the individual level, especially if you consider that a lot of plastic in the oceans come from fishing nets.
It might actually make more sense to stop eating fish, if you want to have less plastic in your ocean.
So generelly: yes, try to reduce plastic, but also make it vocally (and vote) that this is important to you/all of us.
I've worn merino wool underpants on trips where - for various reasons - I took barely anything except the clothes I wore. Hanging the underpants in the steamy bathroom while taking a shower will almost completely refresh them. Heck, even keeping them on in circumstances where showers weren't available didn't seem to pick up any odors, at least for a couple of days.
Not that I would normally recommend regularly wearing underwear for several days or even a week, but wool is clearly superior to cotton or synthetic fabrics.
I also have some military surplus (Finnish M65) wool pants, which are made primarily for warmth and durability, not so much for soft comfort. Even after a sorely-needed rejuvenation with lanolin, they are still made from thick and somewhat coarse wool, which is obviously better for winter pants than silky soft merino.
Personally I don't find wool to be annoyingly scratchy. While I certainly do feel it a little bit when I put on a coarse wool flannel shirt before it warms to my body temperature, but it doesn't bother me. I know some people absolutely can't stand it, but I don't think anyone would have issues with good merino.