Any way to bypass the app?

If you play from a Bluetooth device to your Bluetooth Era pair, isn’t that a direct link without using the app? If so, there’s your answer. 

BTW, I have a number of speakers including a pair of Era 300’s. I find them all to be perfectly useable with the app. 

Google voice control can also be used to playback audio and control the speakers, it just can’t be installed on them. Any product with the GA installed can be used - you just need to install the Sonos action/skill to the Google Home App and scan for Sonos devices.

Hi @Momoi .  You post is incorrect in almost  every respect.  The Sonos app is needed only for initial speaker setup. You can then use BT to play YouTube Music from the YTM app to your Era100s. 

@nik9669a, @John B - Well, I’m glad to hear that! I’ve tried to connect to Bluetooth Era pair from Youtube Music, Soundcloud, etc. and it never works. The speaker does a chime that tells me it’s connected, but no sound come through. I’m obvisouly missing something here, appreciate your guidance. 

@Ken_Griffiths Thank you. I’ve added the Sonos app to GA. For now it doesn’t work either, but will try to troubleshoot

Much appreciated

Please confirm if you have followed the instructions in this article

https://support.sonos.com/en-us/article/pair-sonos-era-100-with-bluetooth

Have you set them up on your wifi network? 
Have you pressed the Bluetooth pair button on the era? What device are you using to pair to the Eras?

FWIW I just paired my.Samsung phone to one of my Era100s in seconds, and the speaker is playing all audio from the phone. So it definitely does work.

@John B @nik9669a Confirming I have done and redone these steps. When I go to YouTube music and click on the Cast button, Sonos doesn't show even tho I'm connected to it with Bluetooth. I read that casting doesn't work with Sonos anyway, so I've tried just playing music directly through Bluetooth, still no luck.

I've resetted the system, clear cache and reinstalled apps, set up the pair, made sure to connect my phone to the pair using the instructions, etc 

Casting isn’t bluetooth. You should connect speakers via bluetooth (once they are set up via WiFi) and they should play anything from your phone.

Hi @Momoi . If you are trying to cast you are not following the instructions. And please stop resetting things!!

Make sure your phone and speaker are on check that Bluetooth  is enabled on your phone. WiFi. Follow the instructions to get a solid blue light on the speaker 

In the BT settings on your phone, pair to the speaker. Then just play something on your phone, ad if trying to use the phone's speaker.