Congrats on the 300 to 400 miles per week of riding. That is a lot of time on the bike and a lot of Kjoules.

First, I use an Apple platform OSX software such that some client based software will not work. I use Cycling Analytics that is cloud based software using a Safari or equal browser as the client software / user interface. My Garmin 830 uploads the ride results to Garmin Connect via my WiFi and Garmin Connect interfaces with Cycling Analytics and Strava (free version).

I use the free version of Strava to get average power per lap and lap times on a local 4.1 mile time trial course. I could use CA but Strava is more convenient.

Cycling Analytics has a lot of features including charts and graphs and offers a programming language called Flexi Charts that allows the user to create custom charts for data over months and years. Want is my best 30 second interval for the last 5 years?

CA determines FTP from the data using different methods and provides the typical performance manager for power or heart rate based metrics.

And Garmin Connect is not bad. My coach has me load my workouts to Garmin Connect that he uses to review my workouts.

Is it CA the best? It is competitive with Training Peaks and may be less expensive over time.