Beautiful portrait.

The phone proves the photo wasn't taken 10 years ago. Today I feel these phones destroy portraiture in general, especially when it comes to candid or street photography. I want to see the Americans with Disabilities Act modified to require accommodations for people who use phones. In many years we may look back on the phenomenom wistfully.

I've been enjoying your photographs and believe you could improve them by giving more exposure.

I treat the 400 speed film as if it had a speed of 250. As you get closer to your subject you might have to calculate bellows-extension.

Chris is right about contrast too. I was going to say develop longer... But I noticed you used D-23, while you have D-76 on-hand.

I had to go look it up because, as primarily a one-film-one-developer guy and I only really know Tmax 400 in D-76.

D-23 is a Metol-based developer, and according to Photo-Lab Index, Metol is great for bringing up shadows but does not build higher densities easily.

So... Making one change at a time, try D-76 1:1 and give more exposure...