Websites, Wifi Speed is slow on my MBP compared to other devices.

The reason we see (and sometimes solve) these kinds of problem here is that your Mac is not used in isolation, it is used in Network Neighborhood, and the stuff around you interacts to possibly change your results.

First step is to Restart in Safe mode, test again, and see if you get strongly different results.

"Works in Safe Mode, fails in Regular Mode" implies, "It's something you added"

I know you said you had a very short list that included no known offenders, but this is a step that you do anyway, just to rule it out.

Next, Hold down the Option key while you click on the Wi-Fi icon on the menubar. You get a snapshot of Wi-Fi performance at this moment. Screenshot or transcribe the values. Looks like this older one:

also, How many Networks do you see?

While you have that menu open, allow Wireless diagnostics to analyze your environment and setting for obvious problems. And note that there are some other tools in there that may prove useful.

Do you have any non Apple security apps installed: AV, any type cleaner, any type app that's supposed fix your Mac's problems? Apps like Norton and CleanMyMac come to mind. There are others of the same ilk that do more harm than good.

I'm using WPA2/WPA3 Personal and I get full speed and for me and that's 300+ Mbps. But I specifically built my LAN to fully utilize the 802.11ac protocol. Being "good enough" may mean it works but no optimally. Why are you insisting on not using WPA3?

This is what can happen if the 2.4GHz spectrum is too crowded with other Routers in your Network neighborhood.This is from WiFi Explorer, and inexpensive Utility:

(drag and drop on preview to see larger and scroll)

You get what you pay for.. My modem (Arris Surfboard) supports something like 600 Mbps and the router (Linksys EA7300) has similar capability. I forget the exact specs but there's plenty of room for future greater speeds with both.

EDIT: Here's the router: https://www.linksys.com/us/support-product?pid=01t340000046qvvAAA

This is my modem: https://www.surfboard.com/products/cable-modems/sb6190/

Of course you get what you pay for. If you buy a 90Mbps line that's the most you'll get. Same goes for capability of modems and routers. You have to buy, or rent monthly, the capability you want.

As to the differences between devices, they should be similar but also may not be in actual application. Many things affect your signal strength: walls, closeness of large metal objects, your body and so on and so forth. The antennas of the devices are important too.

The router I have is designed to learn where the signals are needed and concentrate in that direction. My experience is that works fairly well once given the chance to learn. That and finding the optimum orientation of its three antennas.

I still say try a more capable router. But a router is only as fast as what the modem sends it. The router being faster than the modern is fine, the other way 'round and you create a router bottleneck.

Good luck.

Internet speed tests test the entire connection, all the way from your ISP through all your software and all your hardware to the end. When you get anything other than "crazy fast" all you know is that it is not what you expected. There is none of the required information to make progress and improve the situation.

If you could post a screenshot of the Option-WiFi screen, we can take a better look at what you are experiencing, and might be able to make it better. You can use the "image Insertion" tool in the reply footer on the forums to include the screenshot file in your reply.

You have connected in the very interference-prone and often very crowded 2.4GHz band, establishing a 20MHz wide data pathway around channel 1, often the busiest channel in crowded areas. Your Router is using Wi-Fi-4, or 802.11n.

Your signal is an amazingly strong -31dB, which suggests you are within inches of your Router. With noise at -95, your signal-to-noise is an amazing 64. It is possible that this is too high, so one quick experiment would be to move your computer a few feet away and see if you get a higher Transmit Rate.

The transmit rate achieved, 65 Mbits/sec, is the fastest you can go on the 2.4GHz band with a 20MHz data pathway with ONE antenna. if yours were the only network you could see, a speed this slow suggests Hardware issues such as a disconnected antenna.

How many Networks do you see under "Other networks" ??

A More modern Router supporting the 5GHz band would likely give better results. In addition, wider data pathways can be set up on 5GHz, and more antennas can be used to get faster speeds.