Look, if this is about “short term return on investment” - look at your local job boards. I strongly suspect of the options that you have mentioned Laravel will come out on top. PHP absolutely dominates the current global market.
I suspect that RoR has peaked and some would even go so far to say that it is in decline. And to assume that Phoenix is going to simply take over for RoR would be naive at best. Back in 2005 RoR didn’t have to deal with the existance of AWS/Azure/Google Cloud Platform.
But you have to decide for yourself if you could work with RoR/Laravel day-in/day-out because they are “frameworks to the core”. Basically they have been optimized to produce a certain type of product in a productive manner. Now while that sounds all very positive the skills you acquire while working with these frameworks are mostly related to way the framework is organized.
While having in-depth knowledge of any particular “sub technology” that is part of the framework should be beneficial, the cultures behind these tools don’t necessarily foster that type of skills development.