Hi ludwidVan, thanks for your question, and welcome to the Obsidian community!
Are you familiar with Obsidian snippets? They’re small CSS files that you can use to customize the appearance. You can read more about them here: Add custom styles
I use this snippet to center tables on the page:
/* Center tables on the page */
.markdown-preview-view table {
margin-left: auto;
margin-right: auto;
}