Do you spend 5 hours designing a simple carousel because you want to make it pixel-perfect?
Design is important and it helps in grabbing attention of people.
But it isn't the most important thing - specially if you aren't a designer.
The time could rather be spent on researching and improving your content or on engagement.
Considering a complete post, it's only the cover slide's design that matters.
You can create a template and use it for the cover slide.
The rest of the slides can have less elements and more whitespace. It saves you time and improves readability too.
With time as you increase the productivity of your content creation process, you can start working more on design and slightly improving it every time.