So what is the prefered way of sysupgrading?
Building a new firmware from source and selecting the userinstalled packages i currently have and sysupgrade that firmware.
or
Using a script that lists currently installed packages and dependencies into a xxx.sh and using a firmware from openwrt download repository?
like this for example: https://github.com/richb-hanover/OpenWrtScripts/blob/master/opkgscript.sh
Thank you
Both are completely valid. When you say "preferred" I would actually say it is a matter of your own preference. Building an image is not hard, but it is presumably more work than using the script method. It is a tradeoff between the extra work of building your own custom image, which is then ready with everything you want vs the simplicity of installing the standard release image and then having the script install all the user-installed packages.
I think it all depends on your needs...
But there I is a third option: instead of building from sources, you can also use the image builder, that creates a .BIN from pre-buiit packages.
Which device are we talking about?
Then, since you are not space restricted, there's nothing to add to the previous statements. Chose as you like.