Hi Bil,
In theory yes, the front glass can be replaced. However, in order to do it correctly, the process requires a vacuum chamber to remove air bubbles from between the front glass and the OLED and a UV chamber to cure the Optically Clear Adhesive (OCA) glue that's used to bond them together.
That assumes you can separate the original glass from the OLED without damage. Even experienced technicians can't guarantee 100% success doing this, and to be honest your chances of success on your first try aren't good. You need a vacuum table to hold down the display and a set of wire guides on each side to hold the thin wire at the right height to cut the adhesive without damaging the screen.
So yeah, vacuum table, wire guides, vacuum chamber and UV chamber; I don't know about you but I don't happen to have any of those lying around my garage.
The upshot is that I wouldn't recommend glass replacement. You can probably accomplish a half-assed version of that repair without the equipment, but figure it's going to look like a badly applied screen protector when you're done. Buying a full screen assembly will give you much better odds of success. Given how new it is, there aren't any screen replacement guides available yet, but I did run across a teardown video. If you compare that to something like a Pixel 7 screen replacement guide, you should be able to figure out what needs to be done.
[link|https://www.youtube.com/watch?v=cKEX8jNNzck|Google Pixel 7a Teardown Disassembly Repair Video Review - YouTube|new_window=true]
Although iFixit sells genuine Google Pixel parts, the 7a is too new so you'll have to look to other suppliers. I see a few being offered on eBay such as this one.
[link|https://www.ebay.com/itm/334883626359|For Google Pixel 7a LCD Display Touch Screen Digitizer GWKK3 GHL1X G0DZQ G82U8|new_window=true]
I did run across sites online offering glass replacement, so that might be an option for you, but you'll have to locate a service yourself.
Of course, as a last resort you can always have Google do the repair, but no idea what it's going to cost you.
Good luck and let us know what you find!