Exercise is required to be a human. Walking 10,000 steps each day is a good rule of thumb, it doesn't require proper shoes, or any equipment. Many people will get there just through their day-to-day activities. If that's unachievable, there are games like Ring Fit which are very accommodating.
Sleep is required to be a human. 7-8 hours a day. It doesn't need to be all at once, but it is so important not to devalue those restorative hours.
Food is required to be a human. Our gut biome is instrumental to cognitive well-being; our brain requires Omega-3 fatty acids which can not be produced within our body, and important vitamins such as D, B-12, iron, etc. are often not available in many processed foods (which is why many are becoming fortified!)
Lacking in all the above is co-emergent depression, as well as a recipe for systemic health issues.