This is a great set of questions, Patrick. This cuts at the heart of taking away the false dichotomy of Joy and Godliness – or better yet that by savoring in God, we cannot savor in anything else. The truth is, and I believe this is what the Book of Ecclesiastes is about, anything as not of the LORD is a vain pursuit – but everything if from God is to be savored and enjoyed in it’s own proper place (category) AS an extension of enjoying God.

So . . .first to the big picture and then to your specific questions . . .
When we think of life, we tend to look at what is right in front of us and assume that it is FOR us. Rarely do we look behind the this or that – whether good or bad. There it is (or will be) and “hmmm, what do I think about that?” Well, that says nothing about the meaning or purpose of Life AND the living of it. The truth that so many have come to understand is summed up most concisely in question #1 of the Westminster Catechism:
Q. 1. What is the chief end of man?
A. Man’s chief end is to glorify God, and to enjoy him forever.
Now, a person might say in a discussion like this, “Yeah . . . it says ‘chief end’, not only end. Sure we are supposed to ultimately do that, but that does not mean that we can’t/shouldn’t do anything else, right?”

Well, that is where guys like Jonathan Edwards and John Piper help to belabor thorough clarity to that statement by unpacking all of that. Inso doing, they help us understand that to have a chief end means that you seek to move EVERYTHING to that end. Anything else would be in competition to the chief end and therefore not an exercise in running to, or even desiring that chief end. Once there is a chief end in mind, everything must then point toward that end. One does not get to the UK from the US by going due North.

This is where we seek a singular enjoyment of God even through the enjoyment of the ‘things’ that He has given us. So, I eat strawberries to the glory of God; and savor in my wife to the glory of God; and delight in spirited dialog to the glory of God. These ‘things’ are gifts from Him (James 1:17), but to stop there, for even a moment, and bask in their glory is almost a raping of the glory that any ‘thing’ might have – that is, if anything is truly delightful (at whatever degree) about it, then it must have in it the delightfulness of God AND SO it exists to bear witness to and direct toward the delightfulness of God. To stop at the ‘thing’ and delight in it is to even rob it of its purpose.

So, our self-denying is first for God and then for self and each other. Our community must be a community of God. Christ did not humble Himself (Phil. 2) just to set an example about socio-ethical life. He did it to the Father, according to His will, making sacrifice SO THAT we could be reconciled and He would be Who He Is – One with a name that is above every name and would be paid homage by every living thing because of that.

Second, to say that, as regards heaven, “if God wanted to be enough, heaven would be a sterile environment” is to miss the point completely. Nothing God makes is “sterile”, precisely because He is not “sterile.” Heaven is again that perfect expression of God, Himself – untainted by sin. As we see late in Revelation, He is the Light and the Temple – the beauty is of Him, NEVER added to Him – there is no Beauty that is “Outside Him” – He IS beauty.

That is where realizing that adjectives are a failing language as relates to God. He is not a Holy God, or a Just God, or a Loving God, or a Beautiful God . . . He IS Holiness, He IS Justice, He IS Love, He IS Beauty. They flow from Him, they do not describe Him.

So as regards God and Him being enough, it is to do with the reality that our joy is to be found in God, alone. Only when the ‘things’ are seen as an extension of Him, will they be in their proper place (category) of being a further delight in Him. This is why sin can never properly be desired or adored – it is antithetical to this principle.