No, but I noticed the same thing (that Invasions wasn't available individually). It's Try asking about it on the official forums.
Green Man Gaming (Authorized selller, not grey market) does have it available individually, though Humble doesn't.
I definitely would. I like the style, the exploration, and the tactical combat. I played it on PC Game Pass a few months ago and was sad when they took it off. Have been watching for a sale on it. It's on sale for USD $7.49 right now on IndieGala https://www.indiegala.com/store/product/age-of-wonders-planetfall/718850
If you want to know for sure it's the right sort of game for you, watch some YouTube gameplay videos.
The Language / EN / JR Arctic World.xml file contains the string text for the display, more specifically it should contain the "JR_ARCTIC_WORLD@JR_ARCTIC_SCENARIO@NAME" link.
You will need to add the XML Language file to the RPK under the Content -> Language menu option.
I recommend using Notepadd++ for editing the XML files. When editing an XML file it will colour the text to make it easier to understand at a glance and when you click on an XML tag it will highlight the related open or close tag.
My friend loves this game to death and plays it on a non gaming laptop.. I think this is the one he has:
https://www.amazon.com/VivoBook-Dual-Core-R5-2500U-Processor-Graphics/dp/B07J9W3HNW
Not sure how close that is to yours.