Macbook Pro 2018 Wifi Uploads Slow

Your Wi-Fi appears to be working just fine. Three antennas are being used to pull a very complex data stream off the airwaves on channel 44 in the 5GHz band.

However, the difference between noise at -84 and signal at only -66 yields a signal to noise of 16, consider just to the "poor" side of unusable. You need to be closer to your Router, or have less solid stuff between your Router and your computer.

If you have many neighbors (a long list of other Routers seen on the Option-Wi-Fi display) it is even more important to increase your signal strength by reducing that distance or improving barriers to signal. With a lot of competition, adding a repeater or another "over-the-air" Router such as a Mesh Router will not help.

Adding an additional Router connected with Ethernet cabling may be an option. Or moving your Router by using a longer Ethernet or phone or CATV cable might be an option.

This is the graphic that helps explain a Wi-Fi extender.

Its claim-to-fame is that in low-traffic areas, it can EXTEND the signal (be repeating it). In a busy neighborhood, it Adds double traffic onto the existing airwaves, improving nothing:

The subtle difference between a brute-force extender and a Mesh Router is that one high channel in the 5GHz band is semi-reserved for the Router-to-Router link for all Mesh Routers.

This is the graphic for ADDING Router(s) to your existing Network using Ethernet cabling. No additional over-the-air data traffic is added:

Every modern Router can do this trick. Just use the same network-name and password and they self-organize. You set "bridge mode" (turn off issue addresses via DHCP) on the secondary ones to turn them into simpler access points.

Congratulations. You got lucky.

In extremely busy neighborhoods, that solution would not have worked because the channel reserved for the connection Router-to-Router is already clogged, and adding more Routers and beacons just adds more traffic.

So if you had tried this and it did not work, you would have to try to get an ethernet cable between Routers.

You can buy a pre-made 100 foot Ethernet cable that is likely to reach most places in most houses/apartments, pull it into place and coil up the excess. (longest allowed cable is 100 meters/300 ft). For a neater job, you can buy Leviton "keystone" Ethernet wall jacks and push down the unstripped wires onto a terminal Block, then plug in a short cable.