Re: SQLite
If you read their "methodology" (https://db-engines.com/en/ranking_definition) you'll see it's basically a social media popularity contest... i.e. what's the "coolest" not what's the most installed/actually used.
* Number of mentions of the system on websites, measured as number of results in search engines queries. At the moment, we use Google and Bing for this measurement. In order to count only relevant results, we are searching for <system name> together with the term database, e.g. "Oracle" and "database".
* General interest in the system. For this measurement, we use the frequency of searches in Google Trends.
* Frequency of technical discussions about the system. We use the number of related questions and the number of interested users on the well-known IT-related Q&A sites Stack Overflow and DBA Stack Exchange.
* Number of job offers, in which the system is mentioned. We use the number of offers on the leading job search engines Indeed and Simply Hired.
* Number of profiles in professional networks, in which the system is mentioned. We use the internationally most popular professional network LinkedIn.
* Relevance in social networks. We count the number of Twitter (X) tweets, in which the system is mentioned.