If you plan on making money off of your software, dual license AGPL and commercial. True open source developers can benefit from your work for free and contribute, while clients that would rather not have GPL can pay you.
The reason for AGPL is to prevent people taking your GPL code, changing it, hosting it as SaaS, and never disclosing their changes as technically they’re not distributing the software.
Also, your non core business libraries are the most prime candidates for GPL/AGPL. You want to benefit from community contributions to those, not bear the full cost of development and give it away for free without getting anything in return.
Put it this way: when you use GIMP to create a picture, your picture doesn’t have to be GPL. The image you created is your creation, you decide what license, if any, it’ll have. What the GPL demand is that if you make a change to the GIMP code and share that improved version, you have to do so as GPL.
Likewise, people using your language to create their stuff are free to license whatever they create how they please. They do need to share their improvements to your tools as GPL though.
So perhaps the best option for you is to license the runtime for your language (and some basic libraries) as LGPL so people can link to them with their creations. And everything else that isn’t meant to be linked with the user program at runtime can be licensed as GPL.