Helper UI per se won't exist because there are so many little things.

If we talk about riichi then the best tutorial is probably in Kemono Mahjong https://cyberdog.ca/kemono-mahjong/

Personally I'd say Mahjong Soul is the best riichi client out there, that's where I play https://mahjongsoul.yo-star.com/ Extremely streamlined, good QoL features like tile highlighting (dora too), showing waits and options when you are tenpai, custom lobbies (so you can play with friends), and a pretty robust online ranked system. There is a good tutorial too. The big downside is the gacha system which is purely cosmetic and doesn't affect gameplay at all but it can be a turn off for some people.