does apple still make a router?

no, apple no longer sells network equipment

these days they sell thirdparty network stuff Mesh Wi-Fi Networking - All Accessories - Apple

Typical consumer-grade networking hardware, that includes the Apple base stations (routers), which are expected to run 24x7x365, is around 3-5 years ... although they can last longer.

... and no, Apple stopped selling the AirPort base stations in April of 2018. At this point in time there is no belief that they will resume making them in the foreseeable future.

The other thing to consider is that networking technologies are advancing at a rapid rate. Your AirPort Extreme will not be capable of providing the latest features that are now available ... like WPA3 security or 802.11ax wireless performance.

If you are considering replacing yours, I suggest that you continue using yours until it no longer supports your networking goals. Then, I would suggest, looking at routers provided by either Asus or Synology, as a great starting point.

To help you with your decision, I suggest going to the SmallNetBuilder site where they independently evaluate routers from many different manufacturers.