Lexical variables (those declared with my) are not stored in the symbol table. For that, you need a package global, and three two levels of dereferencing:

13:45 >perl -Mstrict -wE "our $x = 25; my $rx = \*x; say $$rx;"
*main::x

13:46 >perl -Mstrict -wE "our $x = 25; my $rx = \*x; say $$$rx;"
25

13:46 >
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This sounds like an XY Problem. What are you really trying to do?

Hope that helps,