I mean, in my personal opinion, it's totally possible to use GPL licensing on software that you then build a business around. You just have to be a little bit more creative and offer more than just rent-seeking on past labor. Some examples of perfectly feasible ways to build a business around GPL or AGPL software without going bankrupt:

1. Providing all of the source and documentation and build tools needed to build something but only providing pre-built binaries or packages for the program if someone pays. That way they aren't really paying for the software but for the human labor that goes into packaging up the software and making it easy and the computer time and hosting storage that that takes up and all of that.

2. requiring people to pay a discounted amount to get the pre-built binaries or packages of New versions of your software, so that your ongoing revenue is tied to continually making improvements to your product that will actually make people want to move to the new improved version, instead of simply charging a recurring subscription, whether or not people actually like the improvements the subscription is making or actually want to upgrade and then forcing them to upgrade or charging a recurring fee to even maintain access to an old version of the software.

3. providing AGPL containerized versions of your server software, but charging a monthly subscription to access the version of that software that you host for your customers, since obviously servers have recurring fees associated with them, that most people wouldn't want to Self-host, simply because it's a lot of work, but those who do want to do that work still can.

4. Providing good customer support

5. Prioritizing working on bugs or features that a lot of people donate a small amount of money to, sort of like crowdfunding individual components of your application.

6. associating your software business with a hardware business, like System76 does

7. Just operating based on donations, but making it very quick and easy and convenient to donate, and the donation system available from somewhere within your software that's unobtrusive but easy to access like Mozilla Thunderbird does. (This is sort of what FUTO Keyboard seems to do).

8. Subsusting on donations but using an indie game style "pay what you can" interface like elementaryOS does.

In general, the trick is just to provide services that actually require ongoing money in compensation for ongoing labor and actually add value to just the bare source code.