Hi. The things you are saying are the best. If you have your datasets optimized, you have already downsize them with a good data model and still no memory, maybe you need to get a better Embedded plan.
I think you can store dataflows and datasets at a different workspace and embed reports that are on a dedicated workspace capacity. When you can't it usually shows a message of a "...free trial embedding..." or something like that. That's an alternative yes.
I hope that helps,
If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.
Happy to help!