How to best implement WordPress blog subdirectory page into html website

I am trying to make my blog page at https://www.globalhealthbridge.org/blog look like the rest of the site at https://www.globalhealthbridge.org/

Is this possible? Is it better to create a subdomain at https://blog.globalhealthbridge.org/ ?

One of the examples I was able to find that I would like to mimic is here: https://www.portal-japan.com/ and https://blog.portal-japan.com/

I am trying to create not only an SEO-friendly site, but also a user-friendly site for my team who will eventually be updating the blog by logging into WordPress.

Any suggestions, feedback, etc. would be greatly appreciated!

Thanks in advance for your help!