The audio delay is usually inherent to the Bluetooth codec available. I’m not sure why it used to be no delay when the Bluetooth device doesn’t even support low latency codec in the first place. Sometimes the delay may be imperceptible, depending on how precise one perceives the timing of the interaction feedback audio and the touch interactions (e.g. the sound of opening the Equipment Screen, the sound of bow charging to the next charge level, etc).
I’m using S23 Ultra, and even with a Bluetooth earphone (Nura True Pro/Momentum True Wireless 4) that features aptX-LL codec, S23 Ultra itself does not support aptX-LL, so just using a Bluetooth device with aptX-LL with S23 Ultra itself is not enough. You will need a compatible dongle to achieve the least delay on a Bluetooth device.
I’m not sure what Samsung’s own codec can do, but so far my audio experience with this game has been consistently good (as in low latency) as long as I am using a USB dongle that supports aptX-LL and I am using a Bluetooth device that supports the same codec. Nura True Pro (now known as Denon PerL Pro) has its own dongle, while the Creative BT-W6 dongle worked well with my MOMENTUM True Wireless 4 and MOMENTUM 4 Wireless headphones. I have a gaming headset that has its own dongle as well but uses WiFi bands instead of Bluetooth, and that certainly has next-to-none delays (I play DJMAX on PC on that headset with no delay adjustment needed).
However, even with aptX-LL, I can still perceive the slightest of delay compared to listening to the sound through the phone’s onboard speakers, and that makes listening to the game audio using a Bluetooth codec that is not of low latency even worse, but this is expected, hence I went through the trouble of getting aptX-LL-capable audio devices to play this game with.
Some apps like Netflix can compensate for the latency and automatically adjust and sync the display of the video with the playback of the audio over a slow Bluetooth device, so we cannot compare it like this since we don’t need to interact with Netflix in the same, time-sensitive manner as MHNow and therefore what works for Netflix cannot work for MHNow.