Edit: Problem solved: East Coastway disappeared from my TSW2 route selection screen. Reinstalling the ECW add-on made it show up again. Maybe the recent 1.33 and 1.34 updates were to blame.
I’m on a standard PS4 and East Coastway still shows up for me in the route selection screen even after updates 1.33 and 1.34 so it must be a new bug that’s only affecting a small number of PlayStations.