There are many decaffeinated versions of tea :) dont worry.
Rooibos tea is caffeine free and a better option in general to herbal teas, i would be careful with Herbal teas as these are originally medicinal drinks used for specific purposes and can lead to toilet runs and other things just as much as anything else...in any case all in moderation.
And if you're curious the caffeine in tea works different to coffee due in part not only to the amount but by the way it is release into the body, it is slow release thus lasts longer.
honestly i've never been affected by caffeine that much so it makes no difference what i drink at night so long as it's not packed with sugar, but i do switch between black, rooibos and green teas regularly depending on my mood and whether i need a specific tea for aches etc.
Everyone plz be cautious about drinking too much tea at one time, theres caffeine in a lot of them.. even milk tea! its fine to drink daily but too much can either make u stay up at night or use the restroom a lot lol
Herbal teas i.e peppermint or chamomile don't have caffeine so if ur looking for an alternative to drink at night that would be good :)