Airport time capsule slow network
My airport time capsule is setup with a 2.4 network(main)that also has a 5ghz option enabled, and a guest 2.4 network. All the networks are secured. Lately (last 2 weeks or so) only the main network has been experiencing very slow response. The speed test on the main network is running at about 11.9 download speed on the 2.4 but 234 download on both the 5ghz, and guest network. We can identify all the devices that show via the time capsule app and nothing is new or unexpected. The latest device additions were an Apple watch 2 months ago and and an old iPad was replaced with a new m1 iPad about 3 weeks ago. Everything else has remained the same. The slow response on the main network occurs when there is no streaming and the devices are directly in line with the time capsule. The time capsule has not been moved in 2 years. We have rebooted the time capsule and the cable modem multiple times with no change. The speed on the main 2.4 network does at times get better, but we have not seen any correlation to anything when it gets better. Any ideas on what is causing this and how to fix it?