Which upgrade makes more sense?

[ShevAmeMG]

I currently have a Yamaha v477 receiver with a set of 5.1 Cambridge Audio Minx satellites/sub. The surround satellites are plugged into an adaptor to make them "wireless" (they're still connected to a box which connects to another adaptor connected to the receiver via wifi. It works ok, but I notice lots of loss due to that (and quality of this adaptor in general).

All that to say, I'm looking for an upgrade of the receiver so it enables me to have actual wireless (well, connected solely to the power). So far my favorite is an Yamaha RX-A780 which I've been looking for more than a year now, so may already be dated. What you folks think? Would You suggest something else?

Side question: is there any modern a/v receiver which supports PIP (picture in picture)?

Thanks!