As for buying a machine, I highly recommend going to a gym during a quiet period if you can find one that will let you do a trial or a day pass. Then you can try all the machines and find the one that you think sucks the least. Rowing is good because it does loads of muscle groups, but ultimately that doesn't mean anything if you hate it.
E: the thing that changed the game for me was a good hr monitor. Smart watch was full of crap, and just listening to my body made me go way too hard too fast.
The sun is too hot, the wind is too cold. The puddles are a twisted ankle just waiting to happen. I don't want people to see me running - it makes me self conscious of every part of my body and my running form. I don't want to check the little free library during my exercise - that's a break in my flow.
On a machine, I don't have to worry about any of that. I just go, and when I reach my time goal, or I don't feel like it anymore, I stop. I can close my eyes if I want to without worrying about falling over. I can make all the exertion noises I want to if it's hard. I don't have to walk all the way home if I go too hard too early by mistake and get a stitch.
And the best bit is that your way and my way are both totally valid ways of exercising. The important bit is not how we exercise, the important bit is that we exercise.
Meanwhile, I go to kung-fu training and get pretty annoyed when I have to skip a class once. Sports can be wayy more fun and I wouldn't worry about the social aspect so much - adults can behave better than teenagers.
For me, all common forms of exercise feel like torture when doing them, or when thinking about doing them, or both. Most of it isn't even for physical reasons, just a combination of anxiety, procrastination, and the kind of general sports aversion you develop when you get prescribed glasses when you're 7 y.o. and thus go through 10+ years of schools not being able to effectively participate in team sports during PE classes...