According to Eric Berger's anonymous source it is highly likely, that after few launches NASA will drop SLS and Orion and switch to Dragon + Starship.
1. HLS launched to LEO
2. refueled
3. astronauts launched to LEO on a Dragon
4. dock HLS
5. Earth-Moon-Earh roundtrip on HLS
6. Dragon launched to LEO
7. dock HLS
8. astronauts splash down on a Dragon
Even if Blue Origin enters the game they'll go a similar route (maybe with Starliner, hopefully being flight approved till then).
There is no rational reason to keep SLS on the long run, even if costs are not considered, one launch per year is obviously not enough to maintain continuous present on the Moon.