The difference between envy and striving is understanding where one is currently in their life path.
There will always be someone ahead of us, on their path, with years of experience, regardless of age and we may have joined in on this path at a later time. Envy is believing we need to be where they are in regards to career, life, etc. — in essence, saying, even though someone has been on their journey for a longer period than us, upon entering, we should be right next to them, if not, ahead as soon as possible. This is not reasonable, although there are always exceptions to the rule. When noticing these exceptions, for some reason, we compare, envy, and ultimately feel bad about ourselves, pushing to the point of breakage as if making up for lost time when there is nothing to lose to begin with.
By understanding that although there are exceptions, ultimately we each are on our own, unique, path, some running faster than others, but at the end, equal, with gifts and abilities, balancing out our existence. To respect our bodies, mind, souls is to surrender into where we are right now, honoring the life we currently live, absorbing each moment as is meant, and through this, receiving the lessons we must learn to grow — to not let anything pass us by because we are too much in a hurry.
The idea of being "satisfied" in where we are in life while never forgetting to look towards the horizon.
One must not forget, future outcomes are infinite, forever changing, and one change in consciousness, one slight shift in perspective, can shift our future completely, hence, there is no need to hold onto, be fixated, by a particular outcome. We may strive for a goal, have dreams, but more importantly, visualize how we want to get there and through the journey, enjoy each moment walking on our chosen path. Smell the roses, pick the fruits, sit down and feel the breeze as right now is only captured in this moment and by understanding how precious this instant is, we begin to let envy fall away and usher in life.