@scotty38 If you can, before complete lock down, go and try them in a camera store, handle and hint you are very interested in buying. Also ask for the competitors (sony, canon, leica etc)
If you have decent lenses, look at a lens adaptor.
I had a d300 and a fair few lenses.
Traded to a used Leica typ240 mp (always wanted a leica, but also wanted full frame), kept a few nikon lenses (105mm macro, lens baby) and got an adapter.
Now got tempted (and GAS) and upgraded to a used m10.
But as I was considering the upgrade, visited the stores to compare z6 and z7. They are light and plasticy. Need a specific memory card. But they have adapters to nikon f mount to save on lens in the short term.... long term trade them to proper z lenses perhaps.
But I always find it best to handle them first. besides its a lot of money.
Or alternatively if there is a rental place in your area/postal, try them out over a week end and compare to your current camera/lenses. See what the differences are. Whichever you like the most, buy that one. Should be considerably cheaper to rent than to buy wrong...
Good luck!