Why PHP warning??

Same here https://prnt.sc/PR5wVW2zpcmY. our php version 8.1 https://prnt.sc/xKsK75MQ2Gkw

“PHP 8.x has been with us for a while now, so much so that even PHP 8.0 has only security support, and we should mainly use PHP 8.1 and PHP 8.2.”

Ref: https://make.wordpress.org/hosting/2023/05/15/is-wordpress-compatible-with-php-8/

In other words, any issues like errors or crashes is most likely due to plugins not keeping up to date with the WordPress and PHP minimum requirements. When a plugin is trying to do the right thing like Dynamic conditions, turning you attention to the other plugin(s) which crashed your website and asking why they are not keeping up to standard should be the approach.