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I’ve got this for movie audio from the laptop - no discernible lag, and I’m quite sensitive to these things. Might be worse if you have one to transmit and one to receive though.
https://www.amazon.co.uk/dp/B07YTKQ78N/ref=cm_sw_r_cp_api_i_jaF1EbY1BZG7B
What are your sources? Could go multi-room at the source with a pair of chromecast audios or sonos connects or something.
Obvs cheapest and most simple is a switch / splitter box and a long pair of speaker cables.
If you have a suspended floor it's relatively easy to run cables under from room to room.