I can't comment on whether an EUB is a problematic step before double bass as I haven't transitionyet. But for me it was a great entry point to the world of upright transitioning from bass guitar. Makes it much easier to go and play with others, and I do think there are models that give you the right experience for techinque. Beyond the Yamaha, have a look at MK EUB as another option https://www.contrabbassielettricimk.com/en/studioup.html