have you tried?
Construct2 with the following premium plugins: Q3D Plugin And Babylon3D plugin in development but has good start, plus its more closer to what unity does, and is easier to use.
if those 2 dont do it for you, try as you said Unity and UE4 both free both have visual scripting in some manner, however they are not even close to the C2 simplicity, they are pitched as simple but are not, are very confusing, unless your already used with their interface.
there are other engines similar to C2 that support 3d godotengine which is free and looks good really(simplicity wise). but i got so used with C2 im to lazy at this point to learn other interface.
also there is blender for windows, and i think there is a addon for mobile platforms also.
here is a list i found on internet some 3d engines with visual scripting / there is also the valve engine there, but i dont recommend it, valve allows u to make games with their engine for free, but you can publish only for free(no monetization/iaps/ads etc).
there might be plenty out there, im sorry if i missed them out, but its really a long list of competitors. id suggest to google and see which fits your needs.
however no matter how simple the 3d software you choose is, you have to think more to graphic assets, 2d is simple to get it done, but 3d ... well its another ball game, atleast when you plan on doing games that require more then blocks and balls or simple shapes (ie. rigged/animated characters).