not having voice overs can make things a little more difficult but not entirely impossible. if you can, I suggest adding voice overs.. it keeps users focused, you can engage discussions however I completely understand if you can't.
Sounds/visual --- you can use stream labs OBS or OBS to assign sounds/gifs etc to hotkeys so when something interesting happens (you win a round, find treasure, beat a boss battle etc) you can hit that assigned key to have something pop on screen to grab attention.
Overlays --- if you're playing a game like among us - you can set a manual slideshow in obs with hotkeys to swap overlays depending what side you're on (See attached gif as an example). Overlays can add an interesting element your videos without needing a voice!
Question of the day/text commentary -- With my streams I use the same overlay technique to add a "question of day" to engage comments! if is a recorded video, adding text on screen when you want to say something can work too!
Text to speech commentary -- I don't usually recommend this one but if its not having audio equipment or just not wanting your voice on video etc, you can use sites like
https://ttsmp3.com/ to insert a written script, choose a voice and download your script as an audio file. I recommend using this very sparingly if you use this option... it can get very overused and result in loss of audience retention.
I hope these help!