Gabriel is juggling being a single father (cooking housekeeping etc) and actually working a job and he relieves the stress and anger of it all by trying to steal ladybug and chat's miraculous. From a tired clerk he becomes a master of someone's feelings, a prideful strategist in this game against ladybug.
Sometimes his akuma fights resolve in silly situations. Like, Gabriel makes 1000 excuses to take a bathroom break which makes his boss think he has some sort of disorder of sensitive matters
Boss: Gabriel, just so you know, I have cystitis as well. So take your time in the bathroom, brother☺️
Gabriel: *death of the ego*
Or he senses a strong emotions while cooking breakfast and leaves to akumatize this person only for him to fail and come back to a plate of burnt food. And now the fridge is empty too!
Nathalie is a good old friend of the Agrestes. She lives nearby and helps them out from time to time. She takes Adrien to school and sometimes shares her 'leftovers' with the family (they are not actually leftovers, she just says that because prideful mister Agreste wouldn't accept any help)
Emilie is still alive, but in the coma in the local hospital
Adrien is still a little popular, but only as kid from the Graham De Vanily family and a childhood friend of Chloe. Later in series he picks up a modelling gig to help his father out. So later when Adrien realises he doesn't want to be a model anymore it's so much harder to tell his father about it.
Gabriel is still pretty much an absent father. He's either never home or zoning out on the couch. And Adrien knows better than to bother him after a stressful workday.