السلام عليكم ورحمة الله وبركاته How long should the friday khutbah and prayer take? Here the khutbah is between 30 and 40 minutes and the prayer is 5 minutes. Half in Arabic and half in Dutch. I struggle with staying awake and having my back unsupported all this time. What is your advice?

The sunnah is to shorten the khutbah and lengthen the prayer, for the Prophet ﷺ said that a man's long prayer and short khutbah are a sign of his understanding (Muslim), though Imam Ibn Baz said there is no harm in lengthening it for a need while moderation remains the basis. There is no particular posture prescribed for sitting during the khutbah, so sit where you can support your back without disturbing those around you, like sitting on a chair or so.