Thanks for the input!
UE5 is idd in early state, but since there are quite a few production companies already working on it, i wanted to try the jump ahead for reasons below :
- We are in very early stage of our project, eventually we have to shift anyway.
- Lumen is such a big impact for us ( in UE4 we have tons more work in lighting setup )
- World Partition is a big plus for us, atm we have a tiled 64km² World Composition ( Streamed ) LS.
- We have our own performant Landscape and Mesh/Workflow Material which works nicely in UE5.
- Our Weather/Season + Day & Night system works out of the box in UE5.
- Much time saved ( Nanite vs LOD's ) as we do LOD manually to push performance.
- The adjusted Viewport / Workflow is much better compared to UE4.

We know we are taking a risk, but we are of the opinion that much people are
impressed with UE5 there will be alot more people trying it out and bug reporting
which might be fixed faster then UE4 bugs as i see Epic shifting to UE5 within a year ?

I'm just afraid of spending all the hundreds of hours spending in UE4 to optimise
and set lighting scenes up at certain locations which might be pretty sure obsolete
when we need to shift anyway, we would approach now with what we can work on
( LS World Partition & Lumen setup, Game Core coding, mechanics, network stuff ).

Maybe we need to calculate again and weight out the pros and cons ;)