Afaik this really isn't true. Most of the drone parts used both by Russia and Ukraine are coming from China, or Soviet surplus.

It used to be much more true. The Biden admin sent a lot more US weapons to fight Russia, Trump used to be much more amenable to send similar weapons provided somebody paid for it.

Nowadays US materiel is either tied up in the middle east or somewhere else (Patriots), or has been neutralized by Russian EW (HIMARS), or the US is just unwilling to part with it for whatever justification.