I recommend an old style “Fixed Card ADF” then turn off all other nav devices and fly a NDB only xcountry, some holds and some NDB approaches….you will vastly improve your math skills. For true fun turn off the HSI / DG and use the standby compass.
An old skillset but it improves situational awareness.
Oh we did refer to IFR fright as “Flying on the Gauges” or sometimes “Dials” especially when telling “tales of daring done”.
A superior IMC pilot was sometimes referred to as “A dragon on the Dials”.
Flying used to be fun..if you weren’t having fun you or the aircraft were doing something wrong.