It is worse than uncompressed, but 990Kbps LDAC is the closest codec to totally transparent I’ve heard for Bluetooth audio. AptX HD is nearly as good to my ears, and is better than 660Kbps LDAC. The differences are very small though, especially when compared with the differences on the analog side, e.g. the amp, and particularly the headphone design.
Apple side-steps the problem by, at least when you’re listening to Apple Music, simply sending the AAC stream as-is to the headphones and has them decode the audio. I don’t know why that isn’t a more common approach.
I’m still somewhat bemused that we’re talking about Bluetooth codecs at all. It surely can’t be that difficult technically to get 1.5Mbps actual throughput on Bluetooth and simply send raw 16-bit/44.1Khz PCM. 2.4Ghz WiFi is capable of hundreds of times that speed. Bluetooth has been stuck at the same speeds for decades.