It is a server-side software which people are required to host themselves.
1: Selling exception. Keep it GPLv3 (or AGPLv3) and offer profitable propriety software to pay you for an exception. The major drawback is that you can't use others gpl'ed software in your software, including patches.
2: Subscription based donation like patreon. It is more stable form of donation if you got a existing user base that is willing to upfront commit to it. License choice is generally best as a community decision.
3: Hosting provider. In this case you want to corner the market in hosting the server-side. If people are required to host themselves than this is obvious a non-option. AGPLv3 is generally a good choice in keeping competition at bay and honest.
It seems like an universal answer to "licenses are too complicated, just do whatever you want with it" scenario.
Hoping to find balance somewhere.