I've never used a coach or training site, but in my 60's I've found two things very useful..
The book :"
The Time Crunched Cyclist" by Carmichael and Rutberg. It has a lot of info on the lingo and science behind effective training, but most important to me is that it had training plans for recreational sportif/century type riders and wasn't 100% focused on racers or Strava segment chasers - and, as the title suggests, is aimed at those looking to spend limited time training.
Zwift is the other. Not only does Zwift make indoor biking tolerable for me, it brings in power measurement to training if you (like me) do not have a power meter on the bike you ride outdoors.
Back in 2019, when I was 62, I loosely did some of the structured training from the book and doubled my outdoor mileage with Zwift miles indoors. I did that to ride in the 209 mile, two-day Seattle to Portland ride and had some of my best statistics ever, though I'm no racer/speed demon in any event. Felt better after 120 miles on the first day than I had previously felt on 100 mile rides.