Our dashboard I’d say is of medium complexity and we are already reaching the CloudFormation template size limits of 1MB. We already minify the spaces to reduce the size even further. And the template takes up 822811/1000000 bytes. This template does not hold anything other than the dashboard and analysis code.
I understand that this is not a QuickSight per-se limitation, but perhaps QS team needs to raise this with the CF team, as I think there was no precedent for this kind of template size before QS assets came into play. Most other resources I know are much lighter on the definition side.