Updating a decade-old portfolio site

I redesigned my portfolio site at tomgeller.com! It's been around for over ten years: First as Drupal 6/7/8, then as WordPress with lots of plugins. 

I decided to take on the challenge of reworking it using only core WordPress — no plugins, no third-party themes. My site had already lost some important functionality when I had to turn off one plugin when it became unstable. I was determined not to let that happen again.

So I boned up on PHP and WordPress theme development -- through LinkedIn Learning courses, naturally. (Specifically, "WordPress: Building Child Themes" by Patrick Rauland and "PHP Essential Training" by Kevin Skoglund.) 

The guiding mandates were:

1. Make the site as stable as WordPress itself;
2. Keep all data, even the irrelevant bits from ten years of development, but
3. Simplify the presentation so users don't see all that old cruft; and
4. Add useful features, such as the ability to play videos on portfolio pages.

More simplification is needed, but it's mostly in grooming the content itself: merging taxonomies, checking links, and that sort of thing. The eternal struggle....

Do you have a portfolio site? What would you change about it? What challenges are you facing to make that happen?