This may not work in every case because of the nature of materials and rendering but there is a way to make it work with the Principled BSDF shader at least.

• After setting color of the object in principled shader…
• Shader Tab > Settings Panel > Change blend mode to Alpha Blend instead of Opaque
• Uncheck Show Backface (by default this gets checked (annoying) when you change to Alpha Blend
• In principled shader change alpha to anything other than 1 (change to zero for complete transparency)
• In Eevee, you will see the result on screen instantly.
• If the object has multiple material colors, you will need to repeat those steps for all materials
• If the fade in and out is part of the animation, you'll need to keyframe the alpha settings