Db Hugger Backpack 30L on Ryanair?

Has anyone flown Ryanair with the Db Hugger 30L? I know it technically exceeds their free underseat bag limit, but given that it's a backpack I'm wondering how strict they are in practice, especially if it's not fully packed.

For reference, I previously travelled with the Db Ramverk 26L on multiple Ryanair flights without any issues, even when packed full.

Has anyone actually been stopped at the gate with it, or does it generally pass without problems?