Methods including introducing a solids-free high-viscosity fracturing fluid (HVFF) into a subterranean formation to create or enhance at least one dominate fracture, introducing a low-viscosity pad fluid (LVPadF) into the subterranean formation above the fracture gradient pressure to create or enhance at least one first microfracture, wherein the LVPadF comprises micro-proppant, and placing at least a portion of the micro-proppant into the at least one first microfracture. Alternatingly introducing a first low-viscosity proppant fluid (LVPropF) and a high-viscosity crosslinked spacer fluid (HVCSF) into the subterranean formation, wherein the first LVPropF comprises proppant aggregates and the HVCSF comprises a gelling agent, a crosslinking agent, and a breaker, and placing at least a portion of the proppant aggregates into the dominate fracture, where the HVCSF separates clusters of proppant aggregates in the dominate fracture. Then, removing hydraulic pressure from the subterranean formation and activating the breaker in the HVCSF.