It's the old tenet of visual media. Show, don't tell. We see Clark and his mother repeatedly exchanging " I love yous", but as you stated, they don't show this love through their actions. It would have been cool if Clark was forced to give up the codex under threat of his mother's death. We would have seen him emotionally vulnerable
It seems like half of film the film wants to retell the Superman story anew, and the other half is like "Alright audience, you already know the story, so we'll skip all of the relevant stuff". It ends up being very disjointed.
Even moreso, it seems like the intent of this film was to showcase Superman's powers, rather than the character. We get a bunch of useless shots of Superman swimming with whales and flying next to gazelles instead of scenes of him protecting people. I love how the first time we see Superman, it's not him using his power to save people, but using it to get justice on some jerk. I know he saved the oil rig at the beginning, but he was on that rig too. It's not like he was actively patrolling and searching for people in need of rescue like Supes usually does.
This movie only gets it half right. Superhero films are about 2 things.
A) individual gets superpowers
B) individual realizes superpowers put them above everyone else
C) individual uses superpowers (read does no neglect them) to perform selfless acts without seeking personal gain
This movie only gets to B), which is incredibly jarring since Superman is arguably the inventor of this system. Let's not forget the infamous "Maybe you should have". The tenet of this film only seems to be "If you have powers, don't abuse them", when it should be "If you have powers, help the helpless". It's like telling a billionaire "don't pick on a homeless person if you walk next to them" when you should be saying "why don't you use some of those billions to buy the guy some shelter?"