[gentoo-user] php different version

i am a little confused.
it's been a few years since i last installed a php application.
but the problems still seem to be the same ;-)

with postfixadmin everything seems to be ok.

when i install nextcloud it also installs php-7.3.31 and php-7.4.24,
this is probably due to dev-php/imagick-3.5.1

if i install roundcube with use="change-password" php-8.0.11 is needed.

i used use="-imagemagick" for nextcloud, and
all packages could agree on php-8.0.11.

1.if an application requires 2 different versions this can't work,
apache only uses one or?

2.if in the ebuild of dev-php/imagick-3.5.1
USE_PHP="php7-3 php7-4 php8-0"
what does that mean?

ty