I know you said you know all the things about ventilation, but it's really the most important thing by far.
When you wake up in the morning make it part of your routine to go around and open all the windows upstairs before you have your shower/get ready for work. Just before you leave, go around and close them all again. Even 5 or 10 minutes a day will make a big difference.
Do the same thing downstairs in the evening while you're cooking dinner (obviously skipping those windows that might cause security concerns if that's an issue).
Just doing that daily will help a great deal.
Make sure, if you do leave windows on the latch while out, that it doesn't invalidate your insurance!
When you're at home (weekend, day off, whatever) leave all the windows in the house open for a good, long while - I make myself a cup of tea and sit in the living room that faces the front for at least 30-45 minutes, that way I'm sure the whole house has got a good airing, and I don't have to worry that someone's going to crawl in through the windows!
After cooking just quickly spray some degreaser or cleaning spray on the splashback/counter tops/cupboard doors and wipe down so that you clear some of the potentially stinky grease. Obviously don't leave food or sorry dishes out. Empty the bins more often.
Wash curtains every so often as they can really hold on to smells.
Essential oils are lovely - I have a basket of pine cones in the front room that I use as a vehicle for oils to fragrance the air.
I'm the same - perimenopausal and my sense of smell has gone into overdrive. I used to think people were being a bit silly when they complained about smelling things too keenly but oh my god it's horrible when you can detect so many levels of odour!