Great question — answering as the UphillTech team:
Which is the best way to solve it. There is no WP based solution to solve this. Any WP solutions will modify the output of a WP theme, but you don't have a WP theme. What you have is a React web application that talks to a REST API and gives the appearance of a WP frontend. To be clear, your React frontend is not a WordPress site, and it is not a WordPress theme. It's a pure JS frontend built in React that grabs content from an API. You can ingest data from WordPress, but generating SEO tags, making your markup search engine friendly, that's a pure React problem that has little or nothing to do with WordPress. There is no way for plugins to change your apps header tags, or other things....
Full answer by Tom J Nowell: https://wordpress.stackexchange.com/a/354502 (CC BY-SA 4.0).
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