The 30 minute workout is a myth...
You're only exhausted after a 30 min workout when you have 0 physical training. After a few weeks it'll have the opposite effects. As developers our body is rotting away day by day, if I didn't push myself to exercise the most physical thing I'd do most of the days is pull a door to open it.
Even a set of dumbbells, a pull-up bar and a stretch mat will be miles ahead of doing nothing. It's very insidious because you can be passive all your youth with almost no side effects, but all those years of passivity will come back at us when we hit 50, 60, 70.
If you're not exhausted after a 30 minute workout that just means you're not pushing yourself.
Even after bouldering for hours to the point of not being able to hold a glass of water in my hand I've never been "so exhausted that the rest of the night is down the drain.", and I'm far from being a genetic freak or a good athlete.
I used to be your average 70kg skinny fat teen, that was 4 years ago when I decided to do something to not end up like all the chubby 30+ years old guys I was seeing daily and who were unable to go up 4 flights of stairs without panting, at some point you have to take decisions for yourself. It's not some bs like "you can be the next Einstein/Musk/Bezos if you try hard enough", there is no luck involved, no barrier to entry. The hard truth is that there is no magic bullet, no quick ways to do it, you just have to get up and move, be it cycling, lifting weight, running, swimming.
It's pure lack of motivation/confidence, once you get started everything falls in place and gets easier. 3 or 4 hours of quality workout a week, even at home, will change your body in a few month and you'll never look back. And if you can't find 3 or 4 hours a week to take care of your most precious physical possession (your body) I guess you have bigger issues to take care of.
I'm currently doing a Texas-method-based lifting program: three-days, medium-light-heavy. The "medium day" is mostly volume with (e.g.) 5x5 squats at 90% for example; I'm zonked after. My light/recovery day I'm only doing 70-75%. The heavy/intensity day it's 1x5 100% (or trying to reach five reps).
Of course if you're going an HIIT program, then yes, you should probably fairly drained afterwards.
Rather than driving 20 minutes each way to the gym, just put on some shoes and run/walk from your front door. You've saved 40 minutes and a bunch of money. Plus, if your goal is to lose weight, you've a far more effective workout.
Walk/run/bike to work. I've completed 2 Ironman triathlons and 75% of my training was done on my commute (my shortest route to work is 8 miles but I can take different routes and make it as long as I want) with hardly any impact (other than exhaustion) on my personal or professional life.
"You can't out run a bad diet"
It should also be noted that there's more to exercise than just weight loss.
> being so exhausted that the rest of the night is down the drain
This is your body's resistance to a change in routine; you may also observe it when, e.g., quitting coffee or skipping breakfast. Keep it up for a few weeks and you'll be over the hump. A couple more months, and a 30-minute workout won't even faze you.
I still don't exercise anywhere near as much as I should. Perhaps the tyranny of distance is the myth?
If you're going to the gym after work (and after getting home) that might be the problem. Everyone I know who works out either can take an extra long lunch break and do it then or get up an extra hour/hour and a half and do it in the morning. It's usually a lot emptier in the morning as well.
Also, there are a lot of activities you can do that don't even involve getting to a gym. You could do a 15 minute jog out and a 15 minute jog back. You can also do most bodyweight exercises at home.