The following will get your fields and values into a hash in one line:

use Modern::Perl;
use Data::Dumper;

my $text = '%MYBOARD{project1|nameofproject1 remarks="Good,Verygood,be
+xt,excellent" grade="7" teacher="Priyanka"}%';

my %data = $text =~/ ([^=]+)="([^"]+)/g;

say Dumper(\%data);
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Output:

$VAR1 = {
          'grade' => '7',
          'teacher' => 'Priyanka',
          'remarks' => 'Good,Verygood,bext,excellent'
        };
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