How would you fill/finish this gap?

[Adsibob]

A year after our main build finished, the builders are due back next week to do snagging. In this photo of our kitchen, there are two joins between the carcass end panel on the left and:

 

1)  the back splash tiles - which has been jointed/filled with regular tile grout

2) the worktop, which hasn’t been jointed/filled at all - there is a small gap, about 0.5mm to 1mm thick.

 

 The grout join on number 1 has started to crack.

 

 Suggestions for filling number 2. Should I get them to redo number 1 with something else? What?

 

Edited May 24, 2023 by Adsibob

[TonyT]

Silicone sealant colour to your choice

[Discoeye]

+1 For silicone and colour to match.