I actually think it’s a Sandman spin off

it was originally a doom patrol spin off but during production it was changed to be set in the sandman universe like the original comic instead. (thus to make it more obviously separate from doom patrol it recast the leads) Likewise I'd like to point out Doom Patrol itself was meant to be a Titans spin off and similarly recast the Chief when it became more of a separate entity. (but in that case kept the rest of the cast of their titans episode)