Currently we are using the ideas section of Aha! as an opportunity backlog, e.g. a bunch of ideas that we could do depending on how well they meet our objective key results (goals). I know Aha! is unlikely to implement "Custom fields for any object type as related tables in reports" see https://big.ideas.aha.io/ideas/APP-I-3607 so this idea would be the next best thing.
Thank you for the request. We can see the value that this would provide. Unfortunately, the same limitations exist with this capability as the one noted in the linked idea.
At this time, we are unlikely to make updates in this area. We hope you can understand.