How have the Russian authorities treated children abducted from Ukraine?

(Yale School of Public Health) Ukraine's Stolen Children: Inside Russia's Network of Re-education and Militarization
(European Parliament) Russia's war on Ukraine—Forcibly displaced Ukrainian children
(OSCE PA Parliamentary Support Team for Ukraine) Russian Abductions and Deportations of Ukrainian Children
(War Child) Return Every Child report
(Le Monde) 'It's like they're coming out of a cult': Ukraine tackles Russian indoctrination of repatriated children
(France 24) ‘Their rights are being violated’: Ukrainian families call for return of their stolen children