Good morning,
I couldn't work out from the picture if it is 6 or 7 speed, if it is 7 speed or it could easily become 7 speed, how about some new Tourney STI brifters?
Of if the frame will take it a new 8 speed Claris groupset, it's cheaper than buying the parts and you can then resell the chainset unused.
..... either way just keep the D/T front shifter.
I found the move from 6 to 7 and 7 to 8 to be real improvements and I am not a fan of keeping things as the factory made them just for the sake of it. Especially if as seems likely the factory would have used a higher spec such as 7/8/9 if they were making it today.
Bye
Ian
It's a 6 speed.