How is the situation with applications in BSD?

I never see an app released for FreeBSD. There are usually Deb and rpm files.

I suppose FreeBSD adapts and releases some them in their ports. But how is the coverage?

Another issue is the hardware support. Does it have drivers for things like recent WiFi chips?

According to repology.org, FreeBSD is the 4th largest package repository in the open-source world.

The deb and rpm files are not from the application either. Someone outside the application took the application and built the deb/rpm for the distro. FreeBSD just calls their packages "ports", but the concept is otherwise the same, just download the package. FreeBSD is better that most distros as is works to rebuild some middle library yourself with non-default options and then have a leaf application binary depend on it (assuming of course that they are compatible, if your non-default option breaks the application it won't work)

Which type of applications? What I have found to be finicky is the desktop environments, however BSDs are pretty much tuned for web servers/applications. Bastille is designed for deploying web applications in jails securely and built on top of FreeBSD which is a pretty good default OS that gets out of your way already.

Normally you don't release an app for BSD specifically unless you want to offer a port. In which case software is usually built and if you need containerization you can put it in a jail.

It seems you would do well to install a FreeBSD vm/usb and give it a run. Their documentation is pretty good and their forums are helpful.