Upgrading/Updating home wifi network with multiple wired access points and addition of some non-apple equipment

Hello All-

I am in the process of revising my wireless network in my house and could use some advice and recommendations for setting up a proper roaming network.

My goals are:

Single SSID.

Ability to add attached storage, and be able to access that attached storage remotely.

Cover a 3000 FT^2 home which has 3 levels, and a substantial outdoor space.

Ability to project wireless signal to a focused area approximately 125 yards away with some trees in the line of sight.

In order to accomplish this, I am willing to buy new equipment and run Cat 6 where ever it may need to go. 

Up until yesterday, I had 200 Mbps service from cable with peak speeds ~240/13

My network set up was roughly:

Cable Modem with static IP -> Cisco MX65W (switch/firewall) -> Time Capsule (and my 5 work computers, but these don’t really play into my issues) -> 2 Gen6 Airport Extremes and 2 Airport Expresses set to “Extend a wireless network.”  One of the Airport Extremes also provided wired service for an Xbox One, and Gen 1 Apple TV.

The wifi functions on the cable modem and the firewall were disabled.

Wireless devices include:

Macbook Pro x 2

Macbook Air

Dell Laptop

iPhone x2

iPad

Nest cameras

Gen 1 Airport express for Airplay

After a bunch of reading over the past 2 days, I realize that this was a stupid way of creating my network and I feel ashamed.  

Yesterday I upgraded my service to 600/35 and when directly hardwired to the Cable router I get ~670/38. I also took down every other device except the Time Capsule and hard reset it before I utilized it.

The current network setup is also connected differently due to the new supplied Modem and Router that provided by Spectrum:

Cable Modem-> Supplied Router with static IP (now with 4 usable ports instead of just 1) -> Time Capsule and (Cisco MX65W switch/firewall and subsequently the 5 computers).

This leaves me 2 additional ports on the Supplied router with static IP addresses.  

When I review the settings on the Time capsule, it is connecting to the supplied router via DHCP, creating a wireless network, and in Bridge mode.

Wireless performance on my MBP 16 is ~670/38 in the office where my Time Capsule resides.  This room is located in the NW corner of my house. 

In the opposite corner of the house (inside), on the same level speeds are ~375/35.  Right outside the house in that corner speeds drop to ~35/29.

Upstairs in the opposite corner of the house speeds are ~200/30.

These results have been widely inconsistent when testing from https://www.spectrum.com/internet/speed-test -  even when making sure that I keep using the same test server.  DL speeds fluctuate from as low as 10 Mbps to full speed from test to test, even when I have my laptop just a few feet from the Time capsule and I am very curious about this wide range of speed test results.

I did a quick test with a 25 ft ethernet cable and attached an Airport Extreme to the Time Capsule and set to “Extend the Wireless network.” The Airport Extreme set itself up in DHCP and Bridge mode.

I moved the router close to an adjacent room where I would have line of site with the Airport Extreme, but the Time capsule would have to broadcast through 3 interior walls.  This increased peak DL speeds from ~350 to ~440, but when I looked at how my laptop was connected, it seemed to have stayed on the Time Capsule the whole time.

Going forward with my plans, I want to have wired connections to the 2 Airport Extremes to fill in the coverage at the opposite corner of the house and hopefully the back yard.  I also want to utilize a Netgear Airbridge WBC502 - https://www.netgear.com/business/products/wireless/wireless-airbridge/

to “beam” a direct signal to a distant location in a particular part of a creek I like to hang out in.  I don’t know if I will really need/want to use the Airport Express units to further extend the network since they only have 10/100 ethernet.  

I also want hardwired connections to my Xbox, and probably the Apple TV too.

One question is whether I should connect my 3 additional wired access points to the Time Capsule, or is there an advantage to also utilizing the 2 empty ethernet connections on the supplied router.  I also plan on using a wired connection to my Xbox and Apple TV, so depending on how I connect the access points, the addition of that switch/or separate connections exceeds the number of connections off my Time Capsule.  

Sorry this is so convoluted, but any feedback/recommendations would be very appreciated!