The first day I would build
Give the city one clear route before adding extras.
- Start with Hoan Kiem Lake and Old Quarter while energy is high.
- Use Temple of Literature as the natural reset instead of crossing town too early.
the easier plan is Hoan Kiem Lake and Old Quarter first, Temple of Literature or mausoleum area separately. That keeps the day readable instead of turning every good name into a separate detour.
I would rather leave one place for tomorrow than drag a tired route through Dong Xuan Market just because it looked close on a map.