I prefer to keep all my code as much as possible mit and I share them on Github. This is my mode of operation.
Grafana makes me unable to use MIT for that use.
Huh? Grafana isn't your code, it's someone else's code that you'd be using. Unless I misinterpreted, and you are a Grafana contributor. If you are, you could dual license your contributions under AGPL and MIT, if you wanted.
This is a stated purpose of GPL3 / AGPL3. I am happy to be told I am wrong and it is possible.
If you are, then your obligation would change to specifically making only that work which builds on top of the Grafana code available to others for free, along with the AGPL3-licensed Grafana code. You are not required to license that code that you wrote in any way, with the caveat that others may freely use it.
If your software is in effect an extension of Grafana, you will need to release source code under AGPLv3.
Edited: Or pick a fork and live on it forever.
Edited: Or write my own Grafana