Years ago, Strava unilaterally disabled the flyby feature on all profiles. They did this without any kind of notice so most people figured the feature was removed completely. Only those who dug around could find that it was a toggle setting in the privacy settings that had to be manually enabled for each person.

You can see Flyovers for your own activities and any other Strava activities you can access. in the bottom right corner of the dynamic map to play the Flyover video. The video will start automatically. You can pause and play, speed it up, or use the scrubbable progress bar to control the speed.

GPX Race Visualizer This is a simple, open-source alternative to features like Strava's Flyby, which require an account and can have privacy issues. For sailing races, it also calculates the distance covered after the 'start' signal and the current speed.