Sony a6400 vs Sony a6700

Hey guys,

I have a problem choosing which camera i should choose as a travel/ B camera.

A little information first. I am a hobby/ semi pro photographer/videographer who, occasionally earns some money with shoots. I already have the Sony a7 M1 and M3. Also i have 4 full frame lenses.

I am looking for a travel/ B camera to take with me on walks and trips. Also to film with occasionally.

I’m waiting to buy the Sony a7 M5 whenever it gets released.

Now the big question is, should i buy a used a6400 with the kit lens 16-50mm F/3.5-5.6 for €600 or a brand new sony a6700 for €1400.

What do you guys think?

Help a brother out? 🙏🏻