SerpAPI is a good service and very easy to use. You can get 100 searches a month for free and $75/month will get you all the searches you (likely) need.

https://serpapi.com

I personally don't find any of these tools to be that trustworthy (because of the level of personalization of SERPs) so consistency and trends is the best you can hope for.

Search for Serposcope to host one locally. Other than that there are many commercial trackers available. Search for 'keyword rankings tool'.

Rank Tracker https://ranktracker.app/

Ahrefs - expensive for individuals, but very much worth it as a business expense.

I found Semrush well worth paying for.