Redirect the entire/whole domain with exceptions

Hi Guys,

I want to redirect an entire domain to a new one using the .htaccess file. However, i would like to implement some exceptions as some pages of the old domain have a new version in the new domain. To do this I have done:

RewriteEngine on
RewriteRule ^/about-us https://www.newdomain/about-us [R=301,L]
RewriteRule ^(.*) https://www.newdomain.com/ [R=301,L]

I have also tried:

Redirect 301 /about-us https://www.newdomain/about-us

RewriteEngine on
RewriteRule ^(.*) https://www.newdomain.com/ [R=301,L]

But none of them work and the old domain redirects entirely to the new one ignoring the exceptions (in this case the about-us page).

I have also tried:

RewriteEngine on
RewriteRule ^/about-us https://www.newdomain/about-us [R=301,L]

RewriteEngine on
RewriteRule ^(.*) https://www.newdomain.com/ [R=301,L]

Can you please help me with this?

Thanks!