More on the theme of odd creatures that drop out of Oak Trees when looking for beetles. This is another that's got me stumped. There were also plenty of Yellow Barkflies (Valenzuela flavidus) so I wonder if this is a nymph (2.8mm) but if so - why has it got wings ? "Google Lens" is stumped as well !

I was intrigued so set about googling and found a Polish site that shows a creature very similar - says it's a nymph of Valenzuela flavidus, as you suspected : insektarium.net/inne-owady/c...

Valenzuela flavidus – Kusolotek żółtoskrzydły

Caeciliusidae – Borowcowate Ubarwienie ciała żółte. Na wierzchu głowy, między oczami, brunatna smuga. Tułów wyniesiony z trzema brunatnymi plamami, które mogą zanikać; plama środkowa często r…

According to iNaturalist a yellow bark louse. Does look freshly hatched 🤷🏻‍♂️

Maybe teneral?