A lot of guessing, but got it at first attempt.

Zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz.

Made a calculated guess and the rest fell into place.

All logical except the last 2.

Thanks.

Full diagonal top left to bottom right.

Thanks.

R1C1 is filled. Diagonal symmetry from there to R10C10.

As JeremyNo says: All logical except the last couple.
I used temporaries part-way through, and it was very easy.