Tackling great design for presentations is what I'm working on with my startup, https://www.beautiful.ai/
We focus on exactly the types of things you're mentioning, but we try to automate it for those who don't have the design skills (or time to invest even if you do have design skills)!
We focus on exactly the types of things you're mentioning, but we try to automate it for those who don't have the design skills (or time to invest even if you do have design skills)!