What really works to protect against mosquitoes is a physical barrier, lots of layers.
To survive the ferocious Oregon mosquitoes I wore pants and a skirt over them (they bit through my pants alone), a T-shirt with a long-sleeved shirt over it (they bit through the long-sleeved shirt without the T-shirt.) I wore thick socks with my shoes (they bit through my shoes!)
My shirt was buttoned to my collar and the sleeves were buttoned at my wrists. I wore a headnet cinched at my collar with my collar turned up so there would not be a gap (they still bit me at the tiny little triangle exposed at my collar button and where the headnet cinched.) I tucked my shirt in so they would not fly up my shirt and bite my chest (they would do that.)
I held my trekking poles so that the straps flapped over my exposed hands. I sprayed 40% DEET on my hat, my shirt and pants. I put some on the backs of my hands and the heels of my hands (they bit the palms of my hands even when I held trekking poles.) That much DEET made me feel sick sometimes.
When I had to pee I used a urinary device so that I could pee standing up without exposing any skin. I made sure to apply DEET strategically in my tent before getting out of it in the morning to begin my hiking. I wanted to be ready for when I needed to do more than pee. I would dig my cathole away from my pack, hoping my pack would serve as a decoy. I would run back to my pack before using my cathole, then run back, hoping the mosquitoes would be confused for a moment and give me peace. That didn't really work, but DEET did.
I lived that way for a month through Oregon. I saw the whole state through a green haze of mosquito netting and DEET-induced nausea. I'm pretty certain that no matter how safe anybody says it is, DEET is quite toxic. At least I have pictures so I can see what I missed.