Good luck. I feel your pain, I too am a big guy - too big for this sport.
How much time do you have? The only thing that worked for me in middle age was long, long, steady distance rides for winter training. I'm talking 15 hours/250 miles per week, combined with intermittent fasting. I'd fast for 36 hours, from dinner one night until breakfast the day after next, once a week.
I was never able to lose weight during the season, I couldn't combine training volume and fasting with the intensity required to stay competitive.