Assuming the Airport is >5years old.. just replace it. And even more so if it is actually purchased nearer the release.. ie 2013, which would make it 8 years old. They do not last forever. Nor are they repairable.
Am I at the point of failure? Do I have to replace my belovedly simple router?
Does your phone or iPad etc have issues with wifi? If not the issue is the computer wifi. Perhaps you need the computer replaced if it is old.
The following assumes you have the problem on all wifi devices.
You can amuse yourself.. reset Airport to factory. Redo the configuration from scratch.
I strongly recommend using short names, no spaces, pure alphanumeric for everything. Passwords same rules but longer.
Use different names for the two bands. eg AE24 and AE5 so when you see those names you know exactly which is 2.4ghz and which is 5ghz. If it drops out .. check which band you are on and try the other. Often one band .. 2.4ghz in my case grows weaker by the day.
Also check signal strength both at the computer and on the Airport.
In airport locate the actual device in the summary and click on it. A new screen will open with actual details.
You do this using the controls on the computer.. hold down option key and click the wifi fan.
This will give you much more info.
Most important is RSSI which is signal strength.
Note they are negative numbers.. so a signal of -46db is much more signal than noise at -87db.
You want signal above -60db at a minimum.. even more on the 2.4ghz band which is noisy.
For me the router is in the room next door and that is the signal at around 10feet through one hollow wall.
Keep track of the signal vs time by using the wireless diagnostics also built into every Mac now.
https://support.apple.com/en-au/guide/mac-help/mchlf4de377f/mac
The report is useless.. so just open the diagnostics and go straight to the menu.
Same as before hold down option while you click the wifi fan.
Select diagnostics.
Do NOT click continue.
Go straight to the top menu and open window.
And open performance.
(With Performance open you can close the introduction).
Performance will track wifi signal etc over a period of a few minutes.
You need to leave this running in the background while you do whatever task you want.. but when the computer drops out check immediately what is happening.
You can use netspot free version.. which is somewhat better to keep track long term but is more intrusive.
This will help you analyse the problem.
Then go and buy a new wireless router and compare..
Or forget the messing around and just go and buy a new wireless router.. or Access Point depending on your requirements.