Timing specific move inputs or combos can be difficult but here's a handy new mod for the PC version of Tekken 7 to help out. Altimor recently released his Input Frame Count Display Mod on Github which will display a small number above the command history in the training mode of Tekken 7 that indicates the frame timing of each input. The Mod itself is a separate code injector program so you have to launch Tekken 7 first then later the mode exe to activate it. Once you have it working though, enjoy some extra data to hopefully help you get some of the more advanced execution stuff in Tekken down. Hopefully this eventually leads into a full blown frame data mod for the PC version? Big thanks go to Altimor for making the mod, you can download it over here:

Tekken 7 Input Frame Count Display Mod ≫ https://github.com/AltimorTASDK/TekkenInputFrames/releases