Choosing LGA over PGA feels contentious to the public if you look at the chatter online but it really comes down to pin density, how many pins do you need on the bottom of the CPU to pin out the features that are in the chip when you can do it with LGA you just do it with LGA because you took or you do it with PGA because the CPU manufacturer can take on the complexity of pinning things our and that complexity is not on the motherboards, you are not shifting complexity to all the different motherboard in the market but
when you reach a certain limit, maybe you are going PCIe Gen 5, DDR5, you've got more features, well you need more pins now and PGA might not be the right choice anymore so we are switching to LGA, it's 1718 pins and its just density you know how much is in the chip and what do we need to put down on the board we needed more pins.
A lot has been said about the shape of the CPU lid and those cutouts are making room for capacitors, surface mounted capacitors, that would have been on the underside of the CPU in a PGA equivalent part but you need all the space you can get on the bottom of the chip so we moved things up top and made those cutouts and that allowed us to keep the same package size as AM4.
It is not pin-compatible but those CPUs are the same length, width, height, and that allows us to maintain cooler compatibility with the socket. (About whether the LID is sealed or not), It is sealed and you're not going to fill it up (With Thermal paste).
