Offers the same as OP's app, except mixing. The only thing I miss is a a fade out possibility. For example, set timer at 01:00 minute and it slowly fades out over that whole minute. Much better than such an abrupt end. Not sure if OP's app does offer that.
Yup, came here to say that too.
iOS Settings - Accessibility - Audio & Visual - Background Sounds
Offers the same as OP's app, except mixing. The only thing I miss is a a fade out possibility. For example, set timer at 01:00 minute and it slowly fades out over that whole minute. Much better than such an abrupt end. Not sure if OP's app does offer that.