All of the things you mention would cause spikes for me because of the level of carbs.
If your preference is for toast then there are low carb breads available on line. They are expensive though. I like a low carb sourdough made by a company called Robert Andrew, but it isn’t the lowest possible low carb bread. I haven’t seen low carb marmalade but I think a company called srsly might do a low carb jam.
Scrambled eggs should be fine on their own…add an extra egg to fill you up if you need to. Or try scrambled eggs with bacon, or cheese. Or another option is Greek yogurt with berries, or with a low carb granola. Keto hana make a range of nice ones available on line and I think in Waitrose and Holland and Barret.