This is a very partial telling of the current situation.
Orion is delayed due to a heat shield issue: https://www.nasa.gov/missions/artemis/nasa-identifies-cause-...
The first SLS launch was six years behind and massively over budget.
Lunar Gateway is almost certainly getting delayed.
None of these programs rely on SpaceX in any way thus far.
"There was no heat shield issue" and "it was investigated and resolved" cannot both be true. There was a heat shield issue; they investigated for two years, and it has caused a delay.
Artemis II has no Starship dependency. It's entirely SLS/Orion.
Your own article agrees with me:
> Artemis 2 likely would've been delayed by a year or so, to late 2026, had a heat-shield replacement been required, NASA officials said today. But the mission team still needs more time than originally envisioned to get Orion up to crew-carrying speed, explaining the roughly six-month push.
> "The heat shield was installed in June 2023, and the root cause investigation took place in parallel to other assembly and testing activities to preserve as much schedule as possible."
There was no heat shield issue, it was investigated and the resolved: https://www.space.com/space-exploration/artemis/nasa-delays-...
There is an issue with another dependency for Artemis 2 and 3, though - Starship is nowhere near where it needs to be.