The main stem looks very delicate which I think is out of balance with the height of the plant and shape and size of the leaves. For the amount of water and light available the plant may be starting to prioritize new growth up to and trying to grow new roots towards the bottom of its thin stem. Some thoughts on what you can do:

• Chop up the stem and propagate and make a bunch of new plants. You could even plant them together in the same pot for a fuller look
• Let the existing stump grow and it will almost definitely put up branching stems
• Run a fan for a few hours a day to encourage the stems to thicken up as new stems grow

Mom’s dracaena was 15 years old and getting scrawny. Only keeping the first few inches of leaves. So a few months ago I did the same thing to it. It’s shorter for now but growing quickly.

Before Image

Cut Image

Replant Image

A few months later Image

I can take a more recent picture later today when I’m out of bed. But where Mom was very nervous me cutting up her one precious plant she has no regrets now. With fuller growth (and a grow light) the plants are looking great.