Or will I take great joy from watching young people have amazing experiences?
This ^
This is why so many Scouters that I know have done 10, 15, 20, 30 , 40 years of more and are still going strong.
Honestly, there are people who let it completely take over their lives. I know people for whom it is their family. So many good friends over so many years. However, you can discipline yourself to do fewer hours, and, indeed, commit to some 'flexibility'.
When you are learning the ropes, it does make sense - if you are able - to go to a few District meetings and events, and even visit other troops to see how other people work too, but it's not compulsory.
There is a training commitment (but you have years to complete it all). Again, if you can make the time, the BEST way to do this is through courses with other people, but, you can do a lot of it through on-line training if that sits better with your life at the moment.
I'm not going to lie, it takes up quite a bit of time in our household, but we consider it our hobby. We have made so many good friends through volunteering with Scouts.