All people, not just the weak, need God constantly. Whether they know it or not, they are relying on Him for their very existence since God sustains all that He has created. He is the source of all of their strength and goods. They also need Him to receive sanctifying grace to get to heaven.
Someone that dies for the Faith will be more glorified in heaven and will spend no time in purgatory compared to someone that converts on their death bed who will be less glorified and will remain in purgatory until the general judgement (without prayers). They all get to heaven, but there are differences. Consider yourself fortunate that God is that merciful.
Those who sin in this world are punished eternally in hell should they die unrepentant, and they suffer in this life with discontent hearts and sometimes the just wrath of God. Those who commit sins of impurity often suffer bodily ills & unhappiness. The saints of God suffer much for Him because it is beneficial to their pursuit in holiness and benefits the whole Church while glorifying God. The saints offer their pains in union with Christ’s Sacrifice to almighty God to gain for themselves countless merits, convert sinners, help the souls of purgatory, &c.
Does that help you at all? You wrote on many points and it is difficult, to say the least, to try to read the block of text.