You might disagree with me, but personally I don’t think you are an expert.
For example, you’re promising error free typing, yet your gig image has a typo in it.
I also checked your PowerPoint video and it’s probably a matter of taste, but most businesses are looking for a clean & simple design, not animations. I used to be a trainer so I’d like to think I’m an advanced user in PowerPoint. If I was looking for a presentation design then I would cut out those distracting animations and focus on content that is presented in a simple and professional way.
Check the portfolio of some of the top rated sellers. You’ll see that there’s a big difference in quality.
If you really want to provide PowerPoint services then buy a few templates with a commercial license and try to offer those with customization.
For example, get a multipurpose template from https://graphicriver.net/item/motagua-multipurpose-powerpoint-template/10348960 and use that as a base. However, keep in mind that those templates need to be purchased for each client separately.
The bottom line is that you can sell whatever service you like and you don’t need to listen to us
However, since you asked I shared my honest opinion and it’s up to you if you take it or not.