Rather sparse on details. From your description, it's hard to know if the issue is the upstream or downstream network that is suspect.
Configs could be useful as a starting point...
also, where is this happening? Are there lots of other wifi APs around? How far are you from the device? Is it connecting to the upstream via wifi or ethernet? if wifi, what is the signal quality to the upstream?
Wired connections in all 3 locations? Have you tried connecting a computer directly to the wired upstream connection (instead of through the 902ac) to test the speed and performance of each connection?
This is not 'hacking', per se. If might be people using your network connection (or possibly the network upstream of yours) which could certainly degrade the experience, but it is not necessarily unexpected nor does it indicate malicious activity.
There's nothign you can do about those other client devices unless they are, in fact, connected to your own SSIDs. Are they? Can you see them on your own SSID when you look at the associated clients?
Let’s see the configs to start. I asked earlier, but now I’ll be specific.
Please copy the output of the following commands and post it here using the "Preformatted text </> " button:
Remember to redact passwords, MAC addresses and any public IP addresses you may have:
…and completely unrelated, you are also that one guy that is in constant worries of being hacked at night by the government and repeatedly looking for ways to get auto-deauthed at night?
Are you sure, there is not some weird config leftover still there from your previous counterhack measures?
I see that neither of your radios has the country code set. Be sure to do that.
Legacy rates should not be enabled here... that is only necessary if you are using 802.11b devices. Turn that off.
Also, what channel are you using?
Change the encryption to standard psk2. Turn off 802.11w (that doesn't apply to WPA2 and may cause problems)
What channel are you using on the 5G network? And, while we're at it, where in the world are you (this will affect the available channels -- see my remark about setting the country code).
Some devices don't work well with WPA3. You may want to change this (for now) to WPA2 (psk2) encryption (and turn off 802.11w)
And for now, you should turn off this since it could be related to your issues. We need to go back to basics to understand which of your configuration settings or packages might be at issue.
Please tell us what channels you are using - it may be part of your issue. And we also need to know where you are in the world... again, this affects the channels that are available to use.
(channel selection is not private/sensitive information -- there are defined channels that everyone must use; it's much like how the RFC1918 private address space is not sensitive either).