How to define a command that defines macro with default value

Question

I have to define a lot of text variables with some default value.
I do it next way:
defname#1{gdef@name{#1}}%
name{Alex}

I tried to automatize this process, but it is not working
newcommand{DefineAndSet}[2]{%
    defcsname #1endcsname ##1{gdef@csname #1endcsname{##1}}%
    csname #1endcsname{#2}
}

My MNWE:
documentclass{article}

newcommand{DefineAndSet}[2]{%
    defcsname #1endcsname ##1{gdef@csname #1endcsname{##1}}%
    csname #1endcsname{#2}
}

begin{document}
    
    DefineAndSet{name}{Alex}
    
    name
    
end{document}

egreg · Accepted Answer

There are several errors in your code: you need to build the symbolic token with csname before def or gdef see it. And the @ should go inside csname.
newcommand{DefineAndSet}[2]{%
    expandafterdefcsname #1endcsname ##1{expandaftergdefcsname @#1endcsname{##1}}%
    csname #1endcsname{#2}%
}

On the other hand, I don't see the need for the @name command.
newcommand{DefineAndSet}[2]{%
  expandaftergdefcsname #1endcsname{#2}%
  #2%
}

would do what you need. With a problem, though: you're not checking whether name (or whatever is produced from the first argument to DefineAndSet) is already defined. This can be overcome by
makeatletter
newcommand{DefineAndSet}[2]{%
  @ifdefinable{#1}{gdef#1{#2}}#2%
}
makeatother

to be simply called by
DefineAndSet{name}{Alex}

How to define a command that defines macro with default value

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