Having used
WorshipTools Presenter (free version) for several years, I recently found
FreeShow. I tested it for a month before deciding to go live for the first time with a new Mac Air M4. It was all set up 20 minutes before the service, 15 minutes before the service, the screen went black, the audio cut out and then it all came back in less than 2 seconds! 10 mins before the service it happened again, so I switched to a backup 2018 Mac Mini and WorshipTools Presenter. Perplexity tells me it's probably a low spec HDMI cable or an HDMI switcher fault. A new Thunderbolt to HDMI has been ordered, so I"ll have time to test it before the next service.
UPDATE.
New HDMI cable seemed to work, I've now used FreeShow for 4 weeks without any issues (even stopped taking a backup Mac Mini along!). I'm probably only using 25% of the features but getting more used to it each week, it's a better program than WorshipTools Presenter (and being free, it's cheaper than ProPresenter!), I'm surprised more people are not using it.