camera replacement dilemma

Hi guys and girls
My Nikon D700 (which I have loved) is now terminally ill and Nikon tell me parts are no longer available.
SO where from here
I enjoy birds in flight and mirrorless sounds sensible.
As Nikon (amongst others) have the ftz lens adaptor so one can use conventional lenses with mirrorless that may be attractive for me
So I have been considering Nikon Z 6ii and Z 7ii - but comments are that autofocus will be a tad slower than D700 and not great for birds in flight
Z9 is stated to get round this and many other problems but is a stack more money (and more than I would really like to spend)
Alternatively Sony and Cannon AF is said to be fester than Nikon Z6/7.
I would be really grateful for any suggestion from any gurus out there
Thank you
Neil Homer-Forbes
My Nikon D700 (which I have loved) is now terminally ill and Nikon tell me parts are no longer available.
SO where from here
I enjoy birds in flight and mirrorless sounds sensible.
As Nikon (amongst others) have the ftz lens adaptor so one can use conventional lenses with mirrorless that may be attractive for me
So I have been considering Nikon Z 6ii and Z 7ii - but comments are that autofocus will be a tad slower than D700 and not great for birds in flight
Z9 is stated to get round this and many other problems but is a stack more money (and more than I would really like to spend)
Alternatively Sony and Cannon AF is said to be fester than Nikon Z6/7.
I would be really grateful for any suggestion from any gurus out there
Thank you
Neil Homer-Forbes