I don’t think it’s necessary to use service user at all times to get the resource unless you are doing any write operation in the repo and are only accessing the nodes inside /content folder. Normally /content folder has anonymous read permission so please revisit your design for this specific use c...

I18N is not possible for components user input. For this you need language translation for your project. Follow this document to identify what’s suits your requirements https://experienceleague.adobe.com/en/docs/experience-manager-65/content/sites/administering/introduction/translation#:~:text=To%20...

Yes you can still achieve this using the embedded or dependencies property of clientlibs placed under /apps using etc.clientlibs. You need to place test2.js in separate clientlibs and test1.js and test3.js in separate clientlibs and add the test2.js as embedded property in clientlibs containing test...

You can use dependencies or embedded for your use case of having on js file dependencies to other js as you explained in your requirements. See below for details https://experienceleague.adobe.com/en/docs/experience-manager-65/content/implementing/developing/introduction/clientlibs however for clien...

Uninstalling the service pack from aem installed via package manager won’t work. If you need to work on previous installed service pack on same then you need to work with previous backup instance. 

I don’t think there is adobe official documentation for your use case but you can achieve this by writing your custom script on docker file. With script your can create a install folder inside crx-QuickStart and place the service pack inside crx-QuickStart/install the sevice pack placed inside crx-Q...

Token based authentic only recommended for development environment. It’s advisable to use service credentials for production in aem cloud service. https://experienceleague.adobe.com/en/docs/experience-manager-learn/getting-started-with-aem-headless/authentication/service-credentials

Is it aem cloud service or ams/on-prem? In aem cloud service you need to configure proxy port but in ams/on-prem it should be straight forward.

Domain name as prefix for all resource paths? can you explain the use case as relative paths automatically get prefixed with domain name .

Get resource from request object as explained on https://experienceleaguecommunities.adobe.com/t5/adobe-experience-manager/usage-of-via-in-sling-models/m-p/283719