I used to do henna in my 20s and liked how it made my hair shiny and soft. It wears out of your hair gradually...at least whatever product I used did...so no roots. There semi snd demi permanent dyes also wear out after about 28 shampoos..so also no roots...or less noticible. I found they didn't really cover the grey..but did blend it in with my darker brown hair. These might be a nice option for you since you don't want to have to worry about upkeep.
Thanks for commenting! Its been good to hear how others feel about this subject!