- Neither can penetrate Obi-Wan's defenses
- If they try to team up to some huge Force attack from 20 at once, it requires too much concentration, and given Kenobi's speed and perception being far above them, he can use that to slaughter them
- His stamina, minimalistic skillset, and incredible experience in fighting sick numbers is perfect for a fight like that
- They can't surround him with 20 at once, 8 at best, and Kenobi is too fast for them, to agile, and he demonstrates top-notch tactical know-how, environment usage and improvisation in the mythos (like his fight against Zabraks on Florrum)
Honestly, I would bet an entire 1$ on Kenobi (which is monthly salary in Poland).