I can relate Anchie. Several things said by other Fabbers seem relevant.
1. Same job- I get this issue since I have owned my same medical practice since 1991 and sometimes feel *so* incredibly stable and boring. I have managed it since 2004 by being part-time there but adding smaller side jobs ( before 2004 the side job was only the kids). This year I resigned the 5.5-year-old current side job due to the stress of Covid. I guess as you are full-time a side job is not an option.
2. A bit depressed and low mood. Partly why I resigned, which has helped. Self-care and knowing limits is good for me.
3. Hair. I have chosen not to dye mine. It can be a bit limiting. And harder to get haircuts this year! No suggestions just sympathy xx
4. I slightly wonder if your software engineer love of spreadsheets is not working in your favour just now? I remember being surprised before when you felt you had to replace all of the too-big items in a certain way? Which you found stressful. This is in a previous post. Then you thought maybe you could manage with less...
5. Mourning past personas and other’s emphasis on them. Just part of time passing and part of ageing, but not easy. I have struggled with my loss of youth and of the unconscious beauty I used to have, but am getting slowly better at coping with it. Just as well since I am nearly 60!
6. Gradual change in parenting role is a big one. Cannot influence their choices and opinions as much.
With all that it is no wonder you are struggling a bit so I just hoped to encourage you to hang on in there.

Anchie - I have felt in a life and style rut previously. You need to change things up. Travel and new activities are how I tend to refresh myself. For me, I would look at learning a new skill. When I want to change up my appearance - I start with the hair. You have beautiful hair - however - it always grows back, so if you want to dye it, cut it - why not?? I love how both LisaP and Janet are sophisticated and edgy - you could reconnect with your former Rock Chic persona, but in a new and interesting way.

Anchie, you mentioned being drawn to the most outrageous items in the window at Zara. But your practical side shot them down. Maybe time to try them on. Even if it ends up being just a laugh. Or maybe you incorporate one/some of the items into your style. Or some particular aspect of them. Color, print, shape, sleeve, detail. Why were you initially drawn to them?

And everything everyone else said.

Agreeing that it sounds like a life rut rather than a style rut. Think about what you want the next phase of life to look like, and then the clothes will follow!