Draft a multi-step funnel SQL query from event data

I want to build a funnel analysis query against an event table. Here is the context:

- Database dialect: {{SQL_DIALECT}} (e.g., BigQuery, PostgreSQL, Snowflake)
- Events table name and key columns: {{TABLE_SCHEMA}}
- Funnel steps in order: {{FUNNEL_STEPS}}
- Conversion window: {{CONVERSION_WINDOW}} (e.g., user must complete all steps within 7 days of step 1)
- Grain: I want results broken down by {{BREAKDOWN_DIMENSION}} (e.g., acquisition channel, country; write 'none' if no breakdown needed)

Please do the following:

1. Write a complete SQL query that counts users who reached each funnel step in order within the conversion window. Use a CTE-based structure so each step is readable.
2. Include a column for absolute users at each step and a column for step-over-step conversion rate.
3. Add inline comments on any non-obvious logic (especially window functions or self-joins).
4. Note which parts of the query would need to change if a user can repeat step 1 (re-entry funnels) vs. first-touch only.
5. Flag any assumptions you made about the schema that I should verify before running the query.