I haven't ever written professional software, but I just took a software engineering course and what I learned is that what technology stack to use is none of the clients business.
Until your client is unable to find competent programmers to hire to do maintenance after you're gone because you chose to use something esoteric.
A big reason why there are so many JavaJobs™ is that there are so many programmers with Java listed on their résumé/CV.
Your client needs to look ahead and plan for the possibility of his/her entire dev team being poached on the same day.
I just wanted to share this because I find it amusing til the moment that client went with another company that had "patent pending tech" and AI, it was sad because I knew the other company was just a couple of guys loading data.
I guess the lesson is that sometimes it's hard for people with a technical background to sell because we usually don't "hype" our tech.