> I dislike using Jira as much as anyone, mainly because it's so excruciatingly slow.

But there is no competing product (suite) that offers comparable functionality and provides the same long-term flexibilty.

This is maybe true, but the future belongs to more flexible software. Eventually Notion [1] or Fibery [2] will replace Jira. They may do it now for smaller team already (10-500 ppl), it just takes time to enter large companies.

[1] https://notion.so [2] https://fibery.io