Psalm 89 is a serious lament to God. The last verse is the doxology for the third part of the Psalter - It fits as an end to this psalm, but it is not a part of the poem. The poem itself ends with the possible allusion to Genesis 3:15, but certainly with a continuing reminder to God that there are promises to be fulfilled.
The poem's structure begins with a concentric first stanza around the pair of verbs: establish and build up. Several words contribute further (coloured in green) here. I have drawn lines to show the structure as well as marking it with colour.
The second stanza - if indeed it is a stanza, is marked by 'the congregation' as opening and closing brackets. The rhetorical question - who is like the LORD is in the centre of that circle with a coda following.
The third section (top of column 2) recalls Psalm 46. In the centre, Sabbath is allowed for the waves of the seas (bless Christopher Smart - Jubilate Agno).
The fourth section has 'lifted up' and 'righteousness' marking the inclusio.
This motif is carried into the third column where the 'lifted up' verb is repeated three times, reinforced by the additional word - horn. Note also the refer-back to the sea and how even the seas are subject to the anointed.
The next long column is bound with the words 'forever', 'seed', and 'throne' - the section spilled over into column 5 ending with the Selah just before the change in mood - so I moved the verses into a single column to see better the concentric structures.
Column 5 balances the power of the verbs at the top of column 2 and the power implied by the covenant promises - as noted in the white on black colours. Here there is no need to 'explain' God's displeasure. There is a 14-fold repetition of the complaint.
Re the final column, where is the concept of 'the anointed bearing on his breast the multitude of peoples' coming from in the poet's mind? It is a primal human experience: the care for others. As Bruggeman points out in his book, Israel's Praise, the Psalms are world-making and the King though the patron of the cult, is also subject to the cost of the tender loving kindness of God: his people and all the others are on his breast. A father with a disabled child who refuses to learn independence and choose the good will know a similar responsibility that weighs heavily on the breast.