Just quickly want to share the gospel of tennis since I've seen it be such a positive part of so many people's lives. I'm not a coach, not remotely pro, just an avid recreational player who couldn't recommend it more to almost anyone of any age or fitness level. Why?

1. It's basically the perfect exercise. No matter who you are, you will exercise more or less near your physical limits for 1 or 2 hours and love every minute. More importantly, you will look forward to every time you get to do this. You might even start to do other exercise just because you want to get better at tennis. I've compared my fitness watch data from playing tennis to a friend who spent a similar amount of time running in preparation for a half marathon. Believe it or not, playing tennis was nearly as good in terms of steps, calories, and heart rate. So what do you want to do? Slog away on a treadmill or something (which let's be honest, you won't do for more than 20 minutes anyway) or play a freaking game?
2. It's cheap and readily available (at least in a lot of areas). Start with a $50-100 racket or whatever is lying around and free public courts. You don't need a team, just one other human.
   It's a good idea to start with some group lessons or something, but that shouldn't set you back too much. Once you get the bug, you will want to spend more on fancier rackets and gear and, if you live in a cold climate, indoor court time (which yes, is somewhat expensive). But none of that is necessary. Start with a friend or join a local league or use a player finder app, etc. Once you find a good way to play regularly, you'll be hooked.
3. It's about as social or competitive as you want it to be. If you want to make some new friends or just interact with another human being every once in a while, tennis is great, especially doubles. If you want to scratch your competitive itch, also great. But these things are totally optional. You can be aloof and casual too. A lot of players love just hitting around, doing drills, etc., without ever playing scored matches.
4. You'll play it your whole life, and you might live 10 years longer doing it:

>A study done by the Copenhagen City Heart Study (CCHS) and published in Mayo Clinic Proceedings followed 8,577 people over 25 years and found that playing certain sports increased life expectancy—with one adding almost a decade to the lives of participants.
>
>One thing the top three—tennis (9.7 years), badminton (6.2 years), and soccer (4.7 years)—all have in common is that they offer more social interaction than individual sports.

Now, the catch: I think the biggest thing that holds people back is that there is a steep learning curve. Good tennis strokes are not intuitive, and you might need to hit around for several months or a year before you can really have a lot of fun playing even lower-level matches. You might feel a little silly hitting shanks over the fence while the players on the court next to you make it look easy. Don't let that hold you back. It's worth it. Youtube is great. Lessons (especially group lessons for beginners) are your friend. Once you get over the initial hump, you'll find there's a huge spectrum of skill levels that have fun playing.

I think the initial difficulty is why pickleball is such a craze right now. And if you love pickleball, great, do it, it has basically all the same benefits, just generally easier and lower impact. But once you get into a groove with tennis, you won't want to play anything else.