The "good ending" in ME3 was added after fans complained about every ending being bad, and it still wasn't good enough for some people.
I'd actually like to know what games you're playing that have these happy rainbow endings. Even in the Final Fantasy series we don't get happy endings, and those games are on the accessible and cheery side of rpgs. In FF7, Cloud was still devastated by the loss of Aerith, and Tifa (who was obviously in love with Cloud) fought through her broken heart and vowed to help Cloud find her. In FF8, Squall died. In FF10, Tidus died. In FF15, Noctis sacrificed himself, and Luna (his love interest) died before him.
It is funny you bring up these examples because I kind of agree (from the "rpg" discussion) that CDPR's CP2077 feels more in line with the jrpg genre than the western rpg genre, and yes most jrps I have played pretty much follow a straight narrative, with generally a pretty bad ending/sacrifice for the protagonist.
Like in western rpgs, yeah you can get stuff like godhood, your kingdom/mansion at the end, lots of "eddies" , everything revolves around you the player etc but in JRPGs, nope, you have to sacrifice yourself to save the world.