URGENT HELP REQUEST! Which online SEO service is BEST?

I need to get up to speed with Keywords and Keyword Phrases FAST. I’m losing customers over this issue. When I run a website audit and compare my client’s website (built with Blocs) against their competitors, I see that the competitors show ranking for indexed keywords, while the Blocs website shows NONE. I have researched to try and find out how to get my client’s site to have indexed keywords, but have not yet found any solution.

Here’s a screenshot of an audit I did on my website compared to 2 other competitors.

I know there are online SEO services like Moz, SemRush, Majestic, etc., but these services are expensive. Does anyone have a recommendation for a service that provides great SEO tools (including Keyword Indexing) but is also affordable?

Any help greatly appreciated!