I am using Bose Companion 5 speakers and came here as after updating to Monterey 12.2 as the speaker icon had a slash through it and I was assuming it no longer worked. However, all I had to do was drag the volume control up to max and it began working again. It seems the update muted the Bose speakers. If others are having this same issue, just try manually increasing the volume in the volume control on the mac. Yeah, I know sounds stupid, but considering I always use the Bose speakers and always have the volume set to max, as instructed by Bose for use with computers, I failed to recognize the muted speaker status as such and thought it was just not working with the Bose anymore.