I've gone some research on this as I've added this data on other sites.
- The 3DS and Wii U data collection stopped some time in 2020, which means limited functionality is possible, and no actual "tracking" can be provided. (Only historical data can be collected.)
- Switch/Switch 2 - The data presented is limited to hour increments for total time, and 15 minutes increments per day. It does track almost every game Switch game played on the account.
The Friend code option seems the most accurate Switch/Switch 2 information we can get as it's down to the minute, but is limited to most recent 20 games, and how often it updates/scraped. The Parental Controls is great for tracking individual days, but that's limited to 5 minutes increments, and also limited to a about 6 months before the data is gone, assuming you had Parental Controls on.