Don’t forget it will depend on the individual and social group and profession just as much as gender.
Professional men may spend MORE on tailored suits and grooming than women if they have narrow shoulders or are short - it isn’t just a case of “off the peg fitted black dress from Karen Millen” as a badly fitted cheaper suit does stand out.
Ditto things like facially shaving every day (men with dry skin and/or eczema have to make sure they aren’t flaking as well). Haircuts have to be very standard for conservative male dominated jobs like the military (never mind having to put on heels and make up - the guys there are on disciplinary action if a single thing is out of place or if the shoes aren’t shined right).
The City is easing up tbh - standard wear for trainee lawyers is “smart business but no ties unless you’re meeting a client”.
Flats and a trouser suit and no make up for women is certainly acceptable in the new graduate employees I know.
I think overall in professions where it’s all about “brain and technical specialist knowledge” rather than “impressing clients” more comfortable clothing is the norm. Think scrubs and crocs.
Badly paid transient jobs like retail and waiting tables often unfortunately draw the short straw in terms of uniform codes for men and women.
I also find there’s a London/non London difference (Londoners go out in black casual wear or workwear that looks good rather than “glamming up” for nights out).
Also a fair amount of class projection /date availability stuff going on - sometimes people want to project they’re on the market for a date (don’t many people meet their partners at work?) . In certain class groups looking “overdone” is looked down on a bit.
Or women will sometimes be a bit snide if they think another woman isn’t dressing similarly “to the group”.
It’s all very multi factoral and gender is just one factor there.