I am in a similar situation, but we are already open for free (that is a must i think at first) I was thinking selling support, offering consulting with the setup etc. but what would be the strategy for having paid support and open github issues at the same time?

Yours is an open source project? The revenue logic there could be very different from a conventional web business.

I don't have any first hand experience with such a situation myself, but perhaps studying some successful cases could get you to the next step: https://www.indiehackers.com/interview/how-charging-money-fo...

If there's some element of open source in your business, you can start here [0] for various ideas on how to monetize.

0: https://github.com/nayafia/lemonade-stand#table-of-contents