I've used Presonus, Focurite Motu and other interfaces.
They are all good.
My current setup is a Focusrite interface and Presonus Studio One.
Papa's recommendation has merit.
If you're just starting with home recording, it's very possible at some point you'll want to upgrade your DAW.
Getting the DAW for free is a pretty compelling argument to choose the Presonus over Focusrite.
About selecting a 1 or 2 channel interface:
In most situations (at home) you'll only be recording one track at a time so, a one channel interface will work.
Adding vocals to a guitar track can be done after the fact.
However, any time you want to record two tracks simultaneously, you'll need a two channel unit.
Even if you can't visualize that happening, I'd always recommend that you start with a two channel unit for future opportunities.
Recording the Katana:
Yes you could go direct into audacity or mic the amp.
However, I'd suggest a different approach.
Don't use the USB, use the line out.
I'd suggest you get a two channel interface.
Put the mic in input #1 and the line out from the Katana into input #2.
That will make the interface your main hub.
Using the USB for the amp and the interface for the mic would require setting up both units as input devises inside your DAW.
That will complicate the setup and recording process.
Mic selection:
A SM57 is a great all purpose rugged mic.
If you grow into your recording undertaking, some day you might want to add additional mics to your arsenals but everyone should have a 57.
One thing to be aware of on the 57, 58 and most dynamic mics...........they are low output, meaning they require higher gain to get good recording levels.
The 2i2 and the audio box both have decent gain on their preamps but I believe they both come in around 50db of gain.
The 57 works best if you have gain in the range of 70 - 80db.
Check the preamp gain on any unit you're looking at and keep in mind more is better for the 57.
If you get an interface with 50ish preamp gain and your happy with the level you get........you're golden.
If you are disappointed with the mic level you can add an additional (in-line) preamp at a later date to boost the signal.
Here's an example of what I'm referring to.
https://www.theseasonedpodcaster.com/gear/cloudlifter-alternatives/