Can't give you help on gym cardio but on your commute mix it up, cadence or full on leg press power on hills.

Make your heart rate rise, don't labour ime.

Log a ride to work via either an app (strava etc) or a bike computer.

1st mile labour to warm up then try hitting a slightly higher speed.

Introduce hills, the most extreme one is to hit a hill in last gear then knock up 1 gear at a time when it gets to much.

Keep at it and your recovery time will increase thus helping with other sports.