It's is hard for me to decide, what I really like to do.

I'm not really sure what to say.  If you can't decide, who should?  Having total strangers run my life doesn't sound like an attractive option to me ;)

Maybe you could use the free time to give each candidate technology a serious try (e.g. implement something non-trivial — but stop after an allotted time) and observe your gut feelings as you go...

This way, you may not have become an expert in any one technology by the end of the free time period, but you may at least have arrived at a decision based on personal evaluation and judgement, instead of letting others decide for you.   Just my 2 cents.