What does the poem say about finding peace?

Ulysses—Odysseus in Greek—is an aging king, bored out of his mind as he vegetates in his palace. In his old age, he's achieved a kind of peace, but it's a sterile peace, a deathly peace that offers neither rest nor consolation. Once upon a time, Ulysses was a brave and noble warrior who fought valiantly in the Trojan War and trawled the seas in search of glory and adventure. But now, in his twilight years, he lingers on, reminiscing about the good old days when he was a true hero, one of the undisputed greats.
Ulysses is so restless, so seized by wanderlust, that he cannot ever find peace in the world of the ordinary and the everyday:

How dull it is to pause, to make an end, To rust unburnish'd, not to shine in use! As tho' to breathe were life!

There's more to life than simply breathing. Yet as he approaches the sunset of his life, Ulysses has no quality of life to speak of; he merely exists. Ulysses can only really find some true measure of peace in death. Until then, however, he must constantly keep himself diverted and occupied with exciting new adventures; he must keep moving or suffer the bloodless peace of a living death.
https://www.poetryfoundation.org/poems/45392/ulysses