As noted its not written in order, and I suspect it is saying the same things repeatedly in different shades. There are seven churches, seven seals, seven angels, seven bowls and seven trumps. These allude to the concept of waiting for the completion of Jesus work, Jesus who is named after Joshua that leader who patiently circles Jericho seven times. Its all about waiting and says as much repeatedly every time it says "This calls for patience on the part of the saints." The saints are the ones who suffer to bring about the end result which is described in symbols. The point of the seven here I think is that we don't know how long just as Joshua doesn't know how many times he must circle Jericho.
You need to understand as to from where this fascination for seven has come about. This is a relic of IE-Aryan people from before the ice-age when they lived in the Arctic Circle. They had month-long dawn and dusk, a two-month long night, and seven months of continuous sunshine. The sun faltered in the eighth month. The IE considered the human race to be formed from the eighth sun.
The Jews picked up the idea from the Zoroastrians when they were in exile in Iraq/Iran.
"saptabhiḥ putrairaditirupa praita pūrvyaṃ yugam l prajāyai mṛityave tvat punarmārtāṇḍamābharat ll"
(So with her Seven Sons Aditi went forth to meet the earlier age; She brought Martanda forward to spring to life and die again.)
https://www.sacred-texts.com/hin/rigveda/rv10072.htm
"Naturally enough we must, therefore, interpret it (X, 72, 9) in the same way where it occurs again in the same hymn (X, 72, 2), viz. in the verse describing the legend of Aditi’s seven sons. The sun having seven rays, or seven horses, also implies the same idea differently expressed. The seven months of sunshine, with their different temperatures, are represented by seven suns producing these different results by being differently located, or as having different kinds of rays, or as having different chariots, or horses, or different wheels to the same chariot. It is one and the same idea in different forms, or as the RigVeda puts it, “one horse with seven names” (I.164.2).
- We begin with the sun. He is described as seven-horsed (saptâshva) in V, 45, 9, and his chariot is described as seven wheeled, or yoked with seven horses, or one seven-named horse in I, 164, 3. The seven bay steeds (haritah) are also mentioned as drawing the carriage of the sun in I, 50, 8.
- Indra is called sapta-rashmi in II, 12, 12, and his chariot, is also said to be seven-rayed in VI, 44, 24.
- Agni is described as sapta-rashmi or seven-rayed in I, 146, 1, and his rays are expressly said to be seven in II, 5, 2. His horses are similarly described as seven-tongued in III, 6, 2.
- Seven dhîtis, prayers or devotions of sacrificial priests, are mentioned in IX, 8, 4.
- Foods are said to be seven in III, 4, 7.
- The chariot of Soma and Pûshan is described as five-rayed and seven-wheeled in II, 40, 3.
- Seven vipras (III, 7, 7), or seven sacrificers (hotârah), are mentioned in several places (III, 10, 4; IV, 2, 15; X, 63, 7).
- Bṛihaspati, the first-born sacrificer, is described as seven-mouthed or saptâsya in IV, 50, 4, and the same verse occurs in the Atharva Veda (XX, 88, 4).
- Seven divisions of the earth are mentioned in I, 22, 16.
- The cows’ stable which the Ashvins opened is said to be saptâsya or seven-mouthed in X, 40, 8."
(Quotes from RigVeda as mentioned in B.G.Tilak's book, "Arctic Home in the Vedas")