Speaking as a person who herself has a hard time throwing out stuff, it appears purging of stuff looks long overdue.

Next it appears your shower door was never configured the right way. You have to walk into your wall to open the door. That doesn't make any sense. If you reposition the shower door then you will have space on the wall to add two wall hung high cabinets. These two cabinets should hold quite a bit. Also maybe it's possible to create storage in your walk in closet.

Also, consider whether you actually use your tub. If you don't, then maybe the answer to both storage and a larger shower is to take out the tub and have a longer vanity opposite a wider shower.

Look for something like this..tall with a lot of storage, put everything you need in it. If it doesn't fit purge and declutter.
(I just grabbed this from Houzz site)

It's never easy to tell some one they need to declutter so please do not take offense. There is an overwhelming amount of "stuff" everywhere, walls included.

It appears the shower was added as an afterthought....
Or the tub. You didn't say what your budget is.
The ideal solution would be to remove both the tub and shower
and install a large walk in shower against that back wall
and get rid of the tub all together.

If your set on a "tub" then same applies but you'll still need to get rid of that old jacuzzi style and replace with a "standard large tub with a shower..

Also, just an afterthought, have you considered moving all of your makeup/accessories etc. to another room?
Possibly in the bedroom? Maybe a cute vanity to free up space in there?

I think I'm on a mission to get people to declutter. How about keeping only what you need on a daily basis in your bathroom. Store the other stuff (if you can't bear to part with it) in a storage area somewhere. My extra stuff is in a cupboard in my laundry room.

Ok looks great. I think I can help with some ideas to improve