This app was mentioned in 3 comments, with an average of 2.67 upvotes
Just last week I found the only app that's even functional with Audio Cues. The free version allows 10 cues per show and several shows (a production could probably be spread over several shows if you have time to switch).
It had a small learning curve for me. I'll probably spring for the $4.99 full version next time I do a show, but there wasn't enough time left in this run to make switching over worth it. I long for the portability though.
I ended up using an app simply called Audio Cues. It's a little clunky, but it definitely gets the job done.
Side note: Your timing is absolutely wild, because I needed to find this app again literally last night after not using it for 2 years.
There seem to be multiple apps that fit the bill:
https://play.google.com/store/apps/details?id=org.radialtheater.audiocues&hl=en_US
https://ampifymusic.com/launchpad/
https://backpackstudioapp.com/
I'd just run an app like this on an old Android phone or iPhone/iPod Touch.