You can use Text web part to add text/headings/paragraphs to your modern page.
Formatting options like styles, bullets, indentations, highlighting, and links are available. You can also paste images inline with text & add tables using this web part.
Documentation: Text web part
You cannot add custom CSS styles using any OOTB web part.
Update from comments:
Microsoft is adding the ability to paste inline images into the Text web part so that images can be closer to text and so that text can wrap around images.
Microsoft 365 Roadmap ID 85584
This feature is currently rolling out to Targeted release tenants & soon will be available for all tenants (standard release/GA)