I'm feeling I'm in a similar boat, just got a powertap c1, got about 185 watts on my 20 minute test. 31, 178cm, 87 kg so a bit fat. I can keep up with the cycling group that used to drop me on every climb now, after about a year and a half of cycling with a similar <10 hour weekly volume. Nothing structured yet though, just some group rides on the weekends and shorter workouts during the week, sometimes some sprints thrown in, tried to mix up zone 2/3/4. I thought progress would have put me at least in the low 200s but damn. I suppose I'll try testing outdoors though.
On a related note, is picrel true? Will I need cat 1/2 training volumes to hit cat 1/2 power numbers? Reading the Bible® rn and just saw a similar chart.