The method getHandlers() does not exist on Psr\Log\LoggerInterface. It seems like you code against a sub-type of Psr\Log\LoggerInterface such as Monolog\Logger.
(
Ignorable by Annotation
)
If this is a false-positive, you can also ignore this issue in your code via the ignore-call annotation
29
foreach ($this->etlLogger->/** @scrutinizer ignore-call */ getHandlers() as $handler) {