When we started work on Chime, there were no viable Go language servers available, so we had all custom stuff. Now, gopls is fairly good, and has been progressing fast. But, yeah LSP isn't the holy grail. Progress on the spec is surprisingly slow, especially given how many holes it has. But, I'm very optimistic that it will get better. There's just so much traction behind it.

However, Chime still contains a huge amount of custom language handling stuff, and will for the foreseeable future. LSP on its own is just insufficient for a good experience.