As others have indicated: I think many people who show others "incredible kindness and inspiration" would value you doing the same for others more than anything you could probably do for them. However, simply telling them "you were incredibly kind to me and you are a big reason for me trying to be kind to others" might just make their day.
Somebody reached out to me 5 years ago to tell me that a small gesture in high school made a big difference in their life.
We’re both into our 30s now, and I never knew her very well, and hadn’t even seen (or talked to) her since I’d graduated. But I did remember the gesture - and even these 5 years later it still makes me happy to remember her thanking me! Like, it didn’t feel like I was doing anything much at all at the time, and I probably would’ve never even thought about it again.
I unfortunately did this to two people that were instrumental in my life, except during a manic episode, and while I sprinkled some good stuff in there, I also said some cringe things that I'm really embarrassed about. Rather than try and apologise many years later, I've just let it hang, and hope they appreciated the good things I said and not the odd out of place manic-inspired things.
This - and probably asking if they know other people that might benefit of your new experience/skills. If they probably helped you, they are still helping someone else too.
100% this. If I run into someone and they say "15 years ago you helped me out with X, and as a result these other great things happened" it will literally make my week.