You want to work with Szymon. Period.
I worked with Szymon in 2016-2018 at Polidea mostly (but not exclusively) on one of the most complex projects - extending Android Lollipop OS for Aevi Albert payment terminal. Actually Polidea hired Szymon with the thought he will manage the project (among other responsibilities) after we realised that the project is much more complex than we initially thought. It was more than 20 people working from distributed locations all over the Europe, where different sub-teams had different priorities and agendas. Szymon delivered that project and much more. He became Head of Client Projects at Polidea and pretty much transformed the whole company to follow great, lean practices when it comes to project management.
The description of Szymon "Project Manager who delivers" is absolutely true. He is one of those rare managers who actually delivers if only delivery is humanly possible, at the same time he will tell you immediately if delivery is not possible.
However limiting abilities of Szymon to "delivery only" (in its narrow definition) is quite an injustice to his skills and personality. I know many project managers who deliver and leave scorched earth behind. That's not who Szymon is. He is one of those very rare birds among project managers who not only delivers but also cares about people, their self-development and at the same time thinks about improving the organization he is in, not only about his project. Usually you find managers who have only one of those traits. It's a rare thing to find some PMs with just two of those. But someone like Szymon who thinks and delivers in all the three areas is almost unheard of.
So just to repeat what I wrote at the beginning: You want to work with Szymon. Period.