I moved my Neos development instance to my production environment.

Edit my .htaccess
setEnv FLOW_CONTEXT Production

Everything runs fine but I think NeosRulez.DynamicResources still compile the Bootstrap SCSS code on every page view and therefore the page ist very slow.

How is it possible to prevent compiling CSSC code and use the minified result on production mode?

I tried out your great boilerplate: https://github.com/patriceckhart/NeosCMS-Boilerplate

but the assets (css/js) are only created when using production mode

FLOW_CONTEXT=Production ./flow server:run

a simple ./flow server:run or FLOW_CONTEXT=Development./flow server:run would lead to this error on the asset url:

Notice: Undefined index: FLOW_CONTEXT in /NeosCMS-Boilerplate/Data/Temporary/Development/Cache/Code/Flow_Object_Classes/NeosRulez_DynamicResources_Controller_ResourceController.php line 57

Is this wanted behavior?
If so, I would make a pullrequest and add this info to the Readme for the NeosCMS-Boilerplate ;)

Using the latest Bootstrap v5.1.2 gives me 2 compiling error:

expecting color, null received: /var/www/neos.dev/Packages/Sites/Raw.Site/Resources/Private/Styles/scss/mixins/_table-variants.scss on line 5, at column 5

expecting color, null received: /var/www/neos.dev/Packages/Sites/Raw.Site/Resources/Private/Styles/scss/mixins/_buttons.scss on line 41, at column 7

If I comment these 2 line out:

// @import "tables";
// @import "buttons";

it works.

Maybe the same: scssphp/scssphp#434 or scssphp/scssphp#440

Can you please update scssphp/scssphp to the latest version?