If you're in your 60s and have a top ten on a Strava climb that's ridden by a significant number of other cyclists, you're doing very well.
Beyond that, just more methodical training and appropriate rest.
I do HIIT once a week *or* a full gas one-hour ride once a week. That's all the serious training I can handle and still recover rather than slowly deteriorate. The rest are lower intensity, longer distance rides, 2-4 times a week. Plus core work and walking. I tried doing more than one interval or FTP session a week but wasn't recovering properly and ended up with chronic soreness and declining speed. Hazard of aging. Some folks might handle more frequent hard sessions but I have to accept what I've got.
I had several top tens and a couple of second places on some tough time trial segments with roller coaster terrain, many short steep climbettes. *Had*. But I knew those wouldn't last. I'm 62, and if I have a Strava top ten it means hardly anyone else is riding that segment. Even a world class athlete in his or her 60s cannot hold off comparably fit cyclists in their 20s-30s. Not unless we're doping or freaks of nature. And I am farrrrr from a world class athlete. I'm slightly better than middling.
I notice this year I lost all my top tens either to younger solo riders (no chance of regaining those) and to stronger middle aged guys riding pacelines. I might be able to nudge back into 9th or 10th if I catch a decent tailwind over my favorite 5 mile TT segment. And maybe add a clip on aero bar. I ain't too proud to use a tailwind, since every solo ride was tailwind assisted, and the rest were in pacelines.
Just being in the top 25% of hundreds of local cyclists, many of whom are pretty dang strong, seems okay to me. Five years ago I was loafing around at 8 mph on a 35 lb comfort hybrid, recovering from a broken neck. I'll happily take the occasional good days now.