If anyone has experience managing wallets on Android, tell me if your funds have disappeared some time?
Be more concerned about the kind of wallet you're using than the type of devise you're accessing it from, the best recommendation for a wallet use is non custodial wallets, then after this has been put in place, know the way you store your key privately and not on that same device being used, be mindful of the things you download on that same device and links you click or sites you visits.
Has Android system spying for private keys?
I mean on a pure Android without any installed apps excepting crypto wallets + google play
If you don't save your private keys on your device you're safe, remember your Google play was connected to the Internet and that has a central server where they store all informations, including your private keys if stored on your device.