The adapter listed here is recommended, but I'm not sure if anyone tested how it works with 4 wiimotes connected simultaneously. Other than that, Atheros BT adapters are rock stable and I can confirm they work fine with 4 wiimotes, but as far as I know they're available only for laptops as combo cards with Wifi...
EDIT: it seems that Asus BT dongles indeed uses Atheros chips, so Asus dongles should work too...
EDIT: it seems that Asus BT dongles indeed uses Atheros chips, so Asus dongles should work too...
Avell A70 MOB: Core i7-11800H, GeForce RTX 3060, 16 GB DDR4-3200, Windows 11 (Insider Preview)
ASRock Z97M OC Formula: Pentium G3258, GeForce GT 440, 16 GB DDR3-1600, Windows 10 (22H2)
ASRock Z97M OC Formula: Pentium G3258, GeForce GT 440, 16 GB DDR3-1600, Windows 10 (22H2)