Hagoromo and Hamura fought the Ten-Tails, not Kaguya. Nothing would indicate they thus needed a space-time technique.lol Hagoromo and Hamura were by themselves when they fought Kaguya which would indicate they have S/T capabilities
Naruto and Sasuke had (Sakura,Obito,Kakashi) assisting them.
Plot was heavily involved in defeating Kaguya especially since they should have died atleast 4 times.
Sasuke was solo in another dimension
Naruto should have been ash boned and captured but for some reason she paused.
Byakagan couldn't see 360 degrees.
I would think it's pretty likely they could beat Hagoromo together.