Do you have to renew your licence to continue using Jira and Confluence?
No, your licence is unlimited in use, you should pay annual fee only if you need support and maintenance. I see no reason why you should. Atlassian support is non-existent, the software is buggy, features requested years ago are still not implemented. There is no maintenance at all, yet the price becomes higher and higher. I don’t think you should financially support Atlassian for the poor level of service they provide.
On the other hand, if there will be a stable version after several unstable releases, you can always pay to update to that particular release in the future, skipping all mediocre one in between.