One app I saw that immediately makes me want this is something that rebinds the useless Rakuten TV button to something else!
LG's interface is pretty insane in places. E.g. there's no button to go straight to the TV guide. There's not even a play/pause button on the remote. You have to press the centre button anywhere between 1 and 4 (yes!) times to pause. The screen brightness control is buried somewhere insane in the settings like "OLED care". The home screen is literally 85% wasted space. Fully half of it is just a big "WebOS" banner.
If I can fix any of those this is definitely worth doing!
I had the same issue as you. I rooted my TV and decided to ditch that Rakuten button too[1]. I was mildly irritated that I had no way of getting current time easily, so wrote a Svelte+Vite WebOS example that does just that. Adding pause/resume should be equally trivial. For things like this, it's actually very little code once you get used to working on the platform, but yeah, the research prior is what takes time.
Not sure if you know this, but you can bind any application to a "long click" shortcut. Hold one of 1-9 buttons for two seconds over an application in the menu and it will bind it. From there on you can just hold said button for two seconds and application starts.
As for UI things, depending on the version of WebOS, you can likely make (some of) the tweaks you want by using bind+mount to make QML files writable (https://en.wikipedia.org/wiki/QML). There are a some people doing small tweaks to the UI, but I don't know of anyone that did any huge changes (since, once rooted, the ads are trivially removed).
And FUCK the input settings not keeping properly after saving. Try plugging in a laptop, set the input to "PC", save the input config. All good. But if you unplug the laptop from HDMI, either end? Setting lost, back to default. Ugh.
LG's interface is pretty insane in places. E.g. there's no button to go straight to the TV guide. There's not even a play/pause button on the remote. You have to press the centre button anywhere between 1 and 4 (yes!) times to pause. The screen brightness control is buried somewhere insane in the settings like "OLED care". The home screen is literally 85% wasted space. Fully half of it is just a big "WebOS" banner.
If I can fix any of those this is definitely worth doing!