Should we move this into another platform like Discord/Slack/Reddit?

Overall, Discord is one of the most popular platforms for communicating with your audience.

But this forum is also a good platform for gathering and sharing information.
But, as with Apache Answer, Discord needs to be customized, add a bot with tickets, and other things to be able to communicate with the community. (if necessary, I can help you with Discord configuration, I have a lot of experience in it :з).

Just as I know you have several platforms, Apache Answer, mail, and Itch forums.
I think it would be hard to keep track of 3 platforms + if Discord is added to it. So I would suggest to use Discord and Apache Answer (and transfer everyone who is there to these platforms, to make it easier for you and people (but whether it will be easier for people, I don't know...)). That people could have access to Discord communication (share their projects and ideas) and have Q&A on community.drafft.
I would also be interested to know if there is a Discord related plugin for Apache Answer, for example to automatically post questions to a specific text channel.
I agree with you that there is a lack of topics, for open communication.

Anyway, this is purely my opinion, from which you can pick something out and ignore something. :зз
I hope I was able to present my, thought, if something in my words is not clear, I will be glad to answer additional questions :з

I really dislike Discord. The conversation are fast-paced and you miss them easily. I think a forum-style platform like this one is much better overall, whether to share information, give feedback, etc.

If I ask a question today, the forum can be easily searched by someone else later in time who has the same issue and might benefit from the same solution, without having to hope that they're asking the question in the right discord channel at a time when someone online will help them.

Usually, when a software or such only has a Discord as a way to reach the devs, I do not use the product xD Or I keep on sending emails after emails to the devs when there is an issue, which isn't convenient for anyone.

Also, Discord is a for-profit, closed-source platform that pushes its Nitro plans on its users. If the community were to grow, which is my hope!, then we would need to "boost" the server with real-life money.

Apache Q&A is open-source and I assume the self-hosted plan is free as it often is. If you are looking for a true forum-like alternative, I am a long-time fan of phpBB which I know to be totally free & open-source. Although I am sure that with some tweaking, Apache Q&A could also do the job.

Either way, I would recommend against opening a third community place. Right now, most of the action is still on itch.io; if it still feels better to switch place because the shop isn't on itch.io anymore or any other reason... then I would advise to only have one community place, a self-hosted one, whether Apache Q&O or phpBB or any other alternative. Much less hassle for you to handle.