You are 7-10 days into flower, so you got another ~3 weeks of growth assuming it is not stunted. All hope is not lost.
I would not top it... As the lower branches grow i'd bend them outward to help reach light. It's so small that you should not cut anything off, imo. Canopy size and DLI primarily dictate yield. Training mostly spreads the growth out more so you get a greater proportion of better quality buds and lower percentage of larf. Can training eke out a few more percent? maybe, but with a small plant i'd keep it simple. No reason to risk stalling it out any more than it has.
the plant looks relatively fine from what i can see in this picture. Maybe, just a genetically small plant as opposed to anything you did. Still review any beahviour/choices made and think about it, but leaves aren't a toxic mess and the internod distances are not anything of concern either.
15-25% of plants are mutants and or weak. It's always good to plant 200% of need and cull the weak. Easy to say if not spending boku bucks on seed. I use my homebrew seeds to plant the extras, which is easier to swallow. I still throw out a handful of plants i paid for, too. A more consistent outcome is worth it to me. (technically i plant 175% of need, but if it fit in a 1020 tray, i'd do 200%)