Warnings with PHP 8.0 – post->ID

Hey,

i’ve set my website to php 8.0 but then there are some warnings, mostly on duplicate posts or move posts to trash or reverse:

First is

Warning: Attempt to read property “ID” on null …
for line 25
if ( get_post_status( $post->ID ) === 'auto-draft' ) {

and then on the “update” line:

Undefined array key “add_custom_body_class”
Line 28

update_post_meta( $post->ID, "add_custom_body_class", sanitize_text_field( $_POST[ "add_custom_body_class" ] ) );