How to keep my hair in a bun daily without damaging it over time

I work in a food place where I have to have my hair put up in a neat bun because of food obviously. We don't wear hairnets, but headcoverings instead. Mine is like a head bandana so part of my bun is exposed. I'm wondering what's the most effective way to put up my hair everyday without damaging it or my roots. I've got thick and long hair(to the lowest of my waist or top of my behind) and I usually have dry hair and feel like my ends especially are frizzy and my hair is wavy and sorta frizzy everyday after work when I take my bun down(my routine is usually dividing my hair in two, making braids, tightly twisting them together and wrapping it into a bun and use those long, straight hair pins).

I'd also prefer to avoid gels and most hairsprays because of chemicals etc. Thanks!