We're in the UK and were lucky enough to have a garden kitchen in the basement, but even then there's a lot of to and froing unless you have two of everything you need and can keep it there
Another who doesn’t understand the to’ing/fro’ ing aspect. In your kitchen, before guests arrive you make majority of salads or sides ahead of time, there may be one or two that may go soggy you can prep but you take 2mins towards the end to finish constructing. You have meat all prepped before arrivals, nibbles done. Plates stacked etc.
Once BBQ is ready to go, meat goes out to BBQ together with utensils and platters to put cooked meat on. That is one trip from the kitchen involving 2 people (and if larger gathering a tray to hold more stuff than hands could).
Once BBQ is 5 mins from being done, one goes to kitchen, 2min finish for any salads, get other salads out of fridge together with any butter/condiments required. Meanwhile BBQ cook platters meat at BBQ and places on outdoor/indoor table (depending on weather/season). You announce to everyone foods ready, please go in and grab stuff to bring out. Everything should now be on bench and you have ‘helpers’, everyone takes a salad or pile of plates or condiments they can carry. All put on whatever table. Wine/drinks on table, beer in ice in esky, to avoid in/out when anyone wants a drink.
When meal is finished, it simply works in reverse. People take it all back inside and dump on bench. People leave kitchen. You then take 10mins to put anything required back in fridge, scrape plates into bin, stack plates etc.
One more trip when desert is up, few helpers back into kitchen, all in/out in one go.
When people leave, you stack dishwasher, any hand washing while the other quickly cleans BBQ.
You learn this endlessly as a child and then become one of the ‘helpers’ as you get older and you just replicate whatever role, be it as a guest at a BBQ or doing your own BBQ. No idea what people find challenging.