Is there a fundamental difference between existing and truly living, and if so, what does it mean to 'truly live?

For me, existing is simply being alive. Truly living in this context is enjoying life. Enjoying is not a constant all day every day thing, it is in moments, and looking forward to things. When something very sad happens, it can take away our happiness from things we used to enjoy, which is really difficult, it is a vicious circle, not enjoying anything and not doing anything that you enjoy. On average, the older people get the better they get at truly living, they figure out the method and our brains feel less mental anguish as we age.

I suppose “living” is spending a lot of your time on things you actually enjoy, not on working your thankless job to earn money to sustain it.
Hence the term “work-life balance”.

Existing: You wake up every day with no particular goals, no energy to do anything, and you just go through your day….day after day.

Truly living: You wake up excited about the day. You have goals, you have plans to meet the goals, you are doing things to make your day more exciting and satisfying.

Living truly means the present, which is now. The power of now is the master of all times. Per Maslow, our goal is to attain self actualization. This means realizing one’s full potential and fulfilling all of one’s capabilities, representing the highest level of human needs.
Existing, on the other hand, means a life devoid of any control and options in it. Such a stagnant life, makes you suffocate without breathlessness, creating a merely slave out of your own self.

@Forever_Free I was just going to reference Maslow too.

^^GMTA

That is up to you as part of your life philosophy.