First off I will start this off by saying rehoming is okay in any instance for any reason. If a dog isn’t wanted or cannot be cared for it is the BEST thing for them to find a different home.
That being said, there are always going to be times where you won’t be able to do everything you want with your dog or everything they want. Life, work, our relationships, health, etc all also need our time and attention and sometimes those things are more pressing then more than one walk a day.
I’m not really sure what your situation is or why you aren’t currently capable of doing the things your dog needs or for how long its been going on, but I will suggest that you try to make small changes. A small play session in the yard or during your walk, maybe you take her with you to a dog-friendly place you frequent. extra walks don’t have to be as long as the other, maybe its only 10 minutes, maybe only 5. A frozen kong, puzzle feeders, and more creative snack and meal based toys go a long away and are a minimal effort on your part. They help keep her brain occupied and she gets the chance to play and problem solve and you can do homework, nap, care for yourself etc if you need to. If you need ideas for recipes or set up @bindisbucketlist on instagram is a great place to start. Some of the stuff is really involved or weird ingredients BUT you can legit do whatever your dog likes. Or merely toss her regular kibble portion in there.
Also, keep in mind that every dog is different, not every dog needs/wants to go outside all day long or wants to chase a ball for an hour. If you are feeling this way bc you are comparing your life and relationship with your dog to people on the internets situation, step away. Evaluate based on your dog and your dog alone. Do you love your dog? Does your dog receive the affection she wants? Is she being fed and watered properly? Does your dog get to go potty at regular intervals? Do you enjoy spending time with her? Does your pup receive some sort of physical exercise? What’s her behavior like inside the house, does she pace and get destructive or does she nap or keep herself busy in an appropriate way? Remember that ALL dogs could be happier. After all things that make dogs happy would be unlimited playtime, maybe murdering the neighbor’s cat, never having to come inside, eating until u puke, owners never leaving without them etc. Stuff that just isn’t reasonable or good for them. I’m sure just about every single one of us could do something to make our dogs happier, but it might mean losing your job lol.
All this aside, if you feel you cannot reliably care for her the way she needs then rehoming is the thing to do. Your apprehension about who she ends up with is evidence you care for her. Sit down and think of some things that would make you feel better, like a fenced-in yard, time to walk her, willingness to do a training class, kids or no kids, experienced dog owner or not, pets in the home or no. Make your requirements list. Contact some people you know who would like a dog, and see if they were interested. Invite them over, or meet them somewhere to get to know them, maybe visit their place, let them meet your pup. Go from there. The right person will come along.
The only one who can know if its the right time is you. No one has any right to judge you, what you are going through, or what you can or cannot handle. All of us have felt overwhelmed, sometimes to the point where we doubted our ability to care for our pets, sometimes rightly so. You are clearly putting her needs first right now by considering rehoming but I can’t tell you if its the right thing to do.