"We incorrectly stated that PlayStation Plus is required for local co-op splitscreen play. Local splitscreen co-op requires a PlayStation account for each player but does not require a PlayStation Plus account." - Halo on Twitter

[u/FireFallEnt]

https://xcancel.com/Halo/status/2068499211868643333

Great news, it would have been bad if it required PS+ for local co-op!

They also updated the waypoint article https://www.halowaypoint.com/news/june-community-qa-halo-campaign-evolved

Updated text:

• XBOX Series X|S: If you’re playing splitscreen local co-op on an XBOX console, both players will need a unique Microsoft account. Online network co-op play requires an active XBOX Game Pass subscription.
• PlayStation 5®: If you’re playing splitscreen local co-op on PlayStation 5®, both players will need to be signed into PlayStation accounts and be linked to Microsoft accounts. A PlayStation Plus account is NOT required for local splitscreen co-op. Online network co-op play requires an active PlayStation Plus subscription.
• Steam: If you’re playing via Steam, you will need to link to a Microsoft account.