Adjust your SEO strategy
As you know, a natural referencing strategy is established over the long term. Indeed, you have to give time to the search engines to analyze all the content of your site (optimizations, tags, images, texts) and to observe its behavior (traffic, acquisition of links, content updates, etc.). The anteriority of the domain name is also a criterion taken into account by Google (so avoid changing your domain name at all costs!).
A natural referencing strategy must be followed and adjusted Search engine optimization is never static. Search engine algorithms evolve over time and your strategy must also adapt to continue to improve the results obtained.
Keep yourself informed of the changes in the algorithms thanks to the specialized press, blogs, etc. Monitor the evolution of your natural referencing by watching the variations of positions in the search engine results on the queries you are studying. Several tools are specialized in this practice: SeeURank and Google Search Console. In case of disappointing results, don't panic, there are always actions to be taken and at times, first page positions take longer to obtain.
Make your keyword list evolve by removing the keywords that are no longer searched for in favor of more targeted keywords. Then modify the content of your website accordingly. Change your tags (re-optimize them!), titles and texts (add more if they are not enough and rewrite them if they are out of date), so that they are always relevant to the keywords you are looking at. Create additional content pages to support the SEO work on one or more queries. The Google Analytics tool allows you to keep an eye on the evolution of your website traffic (audience, origin, behavior, technologies, e-commerce, conversion tunnel...). The study of these data remains extremely important throughout your SEO strategy.