Behaviour for output of Command Substitution working with String variable with Pipes

Question

For simplicity and how source/input of this post for the coming scenarios, observe the following

java --version
openjdk 11.0.13 2021-10-19
OpenJDK Runtime Environment Temurin-11.0.13+8 (build 11.0.13+8)
OpenJDK Client VM Temurin-11.0.13+8 (build 11.0.13+8, mixed mode)

Just in case java command shows the following

 -version     print product version to the error  stream and exit
--version     print product version to the output stream and exit

That's why I use the latter for the following commands scenarios:

Therefore with:

#1
java --version | head -n1
openjdk 11.0.13 2021-10-19
#2
x=$(java --version | head -n1)
echo $x
openjdk 11.0.13 2021-10-19

Until here all is ok and expected.

Now taking in consideration the following:

Behaviour of bash command substitution with command from string in variable

Note I need the approach shown in the previous link to build complex commands according with some options defined by the user through input - assume a command with parameters chosen by the user.

Therefore with:

x="java --version | head -n1"
echo $($x)
OpenJDK Client VM Temurin-11.0.13+8 (build 11.0.13+8, mixed mode) <--- not expected

The output now is different. Why? How to fix it? or what is missing?

I need the same output as Command Substitution without String

Extra Question

Is valid use command substitution with String as parameter? or is a bad practice?

This looks like a duplicate of the question you linked to; can you [edit] it to be clear on what you're asking that isn't addressed there? — Michael Homer, Feb 05 '22 at 01:09
@steeldriver Is that not the same as "the ; (and subsequent arguments) will be passed as literal parameters to the echo command"? — Michael Homer, Feb 05 '22 at 01:35
Yes, I have problems with the | pipe. Is not considered. I did do a research and sadly eval is evil — Manuel Jordan, Feb 05 '22 at 01:41
@MichaelHomer title edited to do mention about pipes. The other link post is without pipes and the commands used are simple echo — Manuel Jordan, Feb 05 '22 at 01:54
It's definitely a dupe of the question that you link to. The second line executes echo $('java' '-version' '|' 'head' '-n1'), which the accepted answer to the dupe explains. — Kusalananda, Feb 05 '22 at 06:34
I found that alias x="java --version | head -n1" works, I am going to do a research if it has some drawbacks as eval — Manuel Jordan, Feb 05 '22 at 13:02

Behaviour for output of Command Substitution working with String variable with Pipes

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