Tiagra 4700 1x setup? looking for a rear derailleur and cassette combo

The Shimano pull ratios are:

• Dura-Ace before the 9-speed upgrade (anything 8 speeds and below)
• Standard (MTB anything 9 speeds and below, road anything 10 speeds and below)
• Road 11-speed (used also by GRX and Tiagra 4700 10-speed setups)
• MTB 10-speed
• MTB 11-speed (very similar to MTB 10-speed so you may find some cheap derailleurs having average of MTB 10-speed and MTB 11-speed ratios)

Neither the standard nor the old Dura-Ace ratio should be used for internal cable routing as the friction is too high for this pull ratio to work well.

All of these are so different they aren't cross compatible with the MTB 10/11-speed derailleur exception.

You need a road 11-speed rear derailleur, or you can also use a rear derailleur that is intended for 10 speeds but shares the pull ratio with the 11-speed systems such as Tiagra 4700.

I understand that Shimano MTB 12-speed uses a pull ratio very similar to MTB 10/11 speeds, but not sure which of these slightly different pull ratios it uses. More likely it uses 11-speed ratio.

I have 11-34 cassette on a bike using the Tiagra 4700 derailleur (medium cage version). That ought to be enough wide range.

Edit: I realized that Tiagra 4700 lacks clutch. You probably want clutch and narrow-wide chainring in a 1x system. So I recommend GRX instead: it has a clutch, and uses the correct pull ratio.