I used \s* in place of (?:^| ) to make it work across blank lines.

use strict;
use warnings;

my $string = <<HTML;
this=x that=x x another=x thing=x

van=x x x diesel=xx xx
HTML

my @array2 = $string =~ /\s*(.+?)(?=\s+\w+=|$)/g;
 
print "[$_]\n" foreach (@array2);
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