There are a few reasons to consider. The first and most common one could be that your dog may be feeling bored (or understimulated, especially if you tend to practice activities and games with your dog that he/she no longer finds challenging or as stimulating as before). Another common reason a dog feels hyper, especially after having exercised and played, is that they haven't yet learned and practiced how to relax and manage their own emotions under different circumstances.
Similarly to the idea of tucking children in at night with a bedtime story, we can also guide dogs to help them go from an excited, agitated, and restless state to a calm one. And so in a similar manner, it's usually a problem pet parents encounter with their dogs within their first few years as they grow from puppyhood to adolescenthood, to adulthood.
This is because young dogs will need time to reach full maturity, mentally and emotionally, and this is where it can seem to be a difficult task when it comes to helping your dog feel relaxed and mellow in all types of different situations.
What you can do: An easy exercise you can practice is to provide your dog with a food puzzle or snuffle mat after a physically demanding activity, to help their brain focus on a more calming task like using their nose which at the same time helps them relax, slow down & regulate their feelings. The activity of snuffle, and above all employing their scent detection skills and scavenging nature is a near guarantee to help any dog relax. Add to this a frozen Kong that they can spend some time on and you'll have yourself a dog that is keeping busy by chewing and above all licking, which also helps dogs soothe and feel at ease once more. If nose and scent-related exercises aren't helping your dog feel more mellow in your home, it would be best to reach out to a nearby trainer so they can visit and assess your dog's home environment, before recommending a few positive reinforcement options you can try!