Drama: a man loses his sister

This movie is quite new (approx 2010-2022) and not so popular, a small independent one (I often remember the names of the cast but here the actors aren’t that famous: right after watching it, I googled the leading actor, saw him in one link, perhaps IMDb, just 1-3 movies were mentioned). Watched it in 2020,2021 or 2022…Drama/romance about an English-speaking man (handsome, short dark hair) who scrapes a living being a musician(?) in England/Ireland/New Zealand and meets a woman (she was French or from other country, presumably actress). At first they’re just friends but eventually they start dating. He lives in an apartment upstairs.

The climax of the story is happening when he, she and his younger sister spend time in a little house with a lake/pond nearby. While the couple is making dinner (or it is an intimate scene), the little girl goes outside and drowns in waters. In the end, they supposedly split up and he feels bad about it.

+ The music was original since I couldn’t Shazam it