I bring my Google Chromecast dongle with me, plug that into the hotel room TV, then cast my playlist from my phone to the TV.
However I'm thinking of buying either Google Home speaker and bringing that, or buying a Sonos speaker. I drive to all my tour destinations so I'm not too bothered about bringing extra luggage. I currently travel with a portable lighting rig, toaster oven, kettle, cooler box, LED manicure kit and about 400 towels