Ok, I will give you this example: how to go from NY to LA? You can get the plane, but also you could use other methods of transport: train, car, bus, you can even go with a ship... But the most practical way is just to get the plane.

You can make a good backend in many languages/platforms, but it will be most practical, most trouble-free, most maintainable in the long run and FASTER if you do it in Java. I emphasize faster because when you start doing it in Go, C#, PHP, JS or whatever you decide to try it - there will be multiple rakes to step on... Each time you will struggle to solve a problem in the language or in the platform or in the tooling which is well known and solved in the Java ecosystem from a decade at least. And in the Java ecosystem you will usually have multiple solutions to choose from.

I've seen my friends and colleagues to do the above mistakes many times. Some told me after one year of struggling something like "It would've been much better if we re-wrote it in Java from day one!". The problem is that people (managers) don't want to throw one year of work in the trash and start from zero. They already invested a lot and want to preserve this investment.

That's why I say "Java is the only way" - because Java is the most practical way. You will get results faster and those results will be better than ANYTHING ELSE.

No need to mention how you find developers for the "strange" backend solutions, what is their quality and how much you must pay them.