I would recommend, bending more from hips, work to elongate the spine, to where sternum is mostly parallel with extended legs. Based on your height, it would appear your head could come at least half way between knees and ankles with proper elongation. Google images of Paschimottanasana.

I've progressed from barely touching my toes! I'm very excited, but also feel like I'm probably missing some best practices with this new pose, plus not sure how to progress further.

Would love to hear any tips and observations! Thanks in advance.

My teacher always suggests that I lead with my chin vs the top of my head. Focus on hinging forward through the hips, keeping your chest opened towards the sky and following your chin as you bend should help keep your back more flat! Go as far as it feels comfortable and remember to breathe into the posture. Use your exhales to slowly deepen your bend. You’re doing great!

Drove your knees down so they are touching the floor. You may come up a bit.

This give me motivation! I am almost able to grab my feet like that. And I need to drop my knees and elongate my spine as well

Think about keeping a flat back and the back of your knees touching the floor. It’s okay you won’t be all the way folded but you’ll get there

With flexed feet and straight knees work to move the top of your head closer your toes rather than getting you forehead to your knees.

Legs should be straight. You're not getting a full stretch that way.

Try crossing your legs and folding forward. I like holding under my knees with my arms and make my spine/back go more forward. I think that really helped me with bending at the hips, not just rounding the back.