This modifies Fedora's libinput package to enable three finger drag by default. You need to have a build environment setup (I recommend a toolbox container). Start by downloading the two patches in this gist.
$ fedpkg clone --branch f43 --anonymous libinput
Cloning into 'libinput'...
remote: Enumerating objects: 1530, done.
remote: Counting objects: 100% (1530/1530), done.
remote: Compressing objects: 100% (1501/1501), done.
remote: Total 1530 (delta 690), reused 57 (delta 10), pack-reused 0
Receiving objects: 100% (1530/1530), 466.84 KiB | 1.24 MiB/s, done.
Resolving deltas: 100% (690/690), done.
$ cd libinput
$ git apply < path/to/libinput.spec.patch
$ mv path/to/3fg.patch .
$ fedpkg local
[...]
$ sudo dnf install <arch>/libinput-1.29.1-2.fc43.<arch>.rpm <arch>/libinput-utils-1.29.1-2.fc43.<arch>.rpm
$ reboot
$ # profit!