Whatever you decide, make the usage limits crystal clear and honor it. If you say long-term guests have full use of the kitchen, balance your own use of it, so they get fair access to it.
I previously stayed at an Airbnb where the host was perpetually in the kitchen for four to six hours in the morning every single day. This is including weekends. Regardless of whether I left and came back or stayed in, he was always in the kitchen from about 7:00 AM to morning to early afternoon. On some days, he stared bashing around in there from 6:00 AM, waking me up. Then he'd be in it again for several hours around dinner. Non-stop slamming cabinets with force, loudly clashing plates, pots and utensils. It was madness. There were times when I'd pass by, and it was clear he was just hanging about in there with no clear objective. I have no idea what the hell someone who isn't in a culinary profession could be doing in the kitchen for so long everyday.
I had very clearly specified to him before booking that I prefer to cook at home, and also asked him to confirm if that was ok, and if I'd have full access to the kitchen. He said he was completely fine with it.
Four days into my week-long stay, I hadn't even touched the package of chicken or the frozen pizza I bought because I could never get in the kitchen for a second at normal meal times. I couldn't even use the **bleep** toaster or microwave for three minutes because he was always underfoot with clutter everywhere. I ended up having to get take out for all meals, and throwing out the raw food I'd bought to prepare.