Oh I hate granola, for some reason this is what major stores prefer… You can either buy plain cereal flakes of various types (oats, wheat etc) mixed together or this forsaken granola, bleh.

I go for something similar to Male Muesli or Protein Muesli from https://onedaymore.net/ , obviously they charge premium price for the convenience of this being premixed by them, so why not reverse engineer and DIY it? :)

Currently I am mixing bags of muesli from different brands to get what I want, but where I live I might as well buy every ingredient separately and mix it that way.

Not sitting alone, but is one of the strongest factors. Like a hard turds, damaging and pushing your already swollen from sitting veins as you push out the turd, also a factor. Add these and others together etc etc . https://scienceinsights.org/can-sitting-too-long-cause-hemorrhoids/

Also sitting for long periods in front of anything.

Yes