Hello. I am looking for a shoulder strap for my RSC2. I don't like this one in the picture because I can't use the mobile phone holder. Some idea? Thank you

Here ya go, this one is very good. Have it myself

https://www.amazon.co.uk/gp/aw/d/B08MSQZK9X/ref=yo_ii_img?ie=UTF8&psc=1

I was wondering - you may be able to use the mobile phone holder if you attach the strap to the right hand side and have the mobile on the left.  the rsc2 has the same connection/thingy on both sides. would that work?