Internet Air Not Working Anymore

About a week ago, my Wi-Fi started to become quite slow, so after a couple of days, I hopped on the phone with a service rep who told me it was due to cell towers being repaired and would have their repairs completed within a few days. This made sense because a huge snowstorm had hit Chicago right after Thanksgiving, so outages would have caused slower internet due to high traffic towards the remaining cell towers. However, the date has passed for the cell towers to be repaired, and my Wi-Fi speed has gotten progressively worse even though I’ve checked on the ATT outage website and have seen there are no outages in my area anymore.

Any ideas on what could be the root cause? I’ve already ordered a replacement router but would appreciate any help/guidance to improve my speed in my current router until the new one arrives in a few days. Thanks!