WAX610Y and WAC540 Bridged Network

I have a WAC540 that is working great, and it's connected hardwired.

There's a driveway gate controller that needs internet access, but no hardwired network available. So, I purchased a WAX610Y (since it's used outdoors), made the WAC540 the root, and WAX610Y the extender. I also used a PoE injector to power the WAX610Y. The WAX610Y also services outdoor clients.

Both connect and formed a bridge across a long driveway. Although it's only 50 feet away, the wireless strength reported "good" (one below "excellent") at -54 dBm. I connected a laptop to the other end of the CAT5e that is connected to this WAX610Y, and I was getting very poor internet speed, something like 5-10 mbps up/down where it's normally 600+ mbps. I reset everything, did firmware upgrade, etc., but I am still having connectivity issues. It's also disconnecting and reconnecting every so often.

Can you tell me if the WAX610Y supports extending the network across the driveway? This is how I have it:

Gate Keypad <-CAT5e-> PoE Injector <-CAT5e+PoE-> WAX610Y <-wireless-> WAC540

WAC540 <-> router <-> internet

Thanks for any advise for getting this to work properly.