michabarlevThere won't be a 'stand alone' Grell app. They seem to be using the SoundID app as an 'out-of-the-box' solution. This will initially facilitate EQing and firmware updates (at the least). As far as I can understand, it has the scope to include further features as well in the future.
Multipoint is apparently being worked upon (and may even come with a post-release firmware update), but not 100% confirmed.
michabarlevNew community manager for grell audio here! Good question. The TWS/1 supports Bluetooth 5.2 with the Qualcomm 5141 chipset; Qualcomm has announced Multipoint connectivity for this chipset, but qualcomm has not implemented it (yet?).