One option, is 215/60R16 tyres fitted to 7Jx16 ET45 rims from the Yeti. However, if you like 225 tyres, then 225/55R16 would fit those rims.
7Jx16 ET45 rims were also fitted to the Superb MK2, but whereas the Yeti used 215/60R16 tyres on this specification of rim, the Superb MK2 used 205/55R16 tyres which have about a 5% smaller outside diameter than 215/60R16 tyres. The outside diameter of 205/55R16 tyres is far too small for the Karoq because the speedometer would over-read by about 10%, ie. 70mph on the speedo would mean an actual speed of about 63mph, and 50mph on the speedo would mean an actual speed of about 45mph, etc.
The difference in ride comfort between 225/55R16 and 225/40R19 is night and day.
As you can see from the two links below, 16" tyres including new rims can be cheaper than 19" tyres on their own.
Vredestein Quatrac 225/55R16 95V
https://www.camskill.co.uk/m139b0s8009p201104/Vredestein_Tyres_All_Season_Car_Vredestein_Quatrac_6_-_225_55_R16_95V_TL_Fuel_Eff_%3A_C_Wet_Grip%3A_B_NoiseClass%3A_B_Noise%3A_71dB
7Jx16 ET45 5/112 57.1 steel rim (from Yeti and Superb MK2)
https://www.mytyres.co.uk/rims/details?vehicleId=182363349315490928&rimCode=ALCAR9257
To get the comfort of a 225/45R18 from a 225/40R19, you would have to underinflate the 225/40R19 by about 3psi.
To get the comfort of a 225/50R17 from a 225/40R19, you would have to underinflate the 225/40R19 by about 7psi.
To get the comfort of a 225/55R16 from a 225/40R19, you would have to underinflate the 225/40R19 by about 9psi.
So, if you want a night and day difference from a 225 tyre on the Karoq, go for the 225/55R16 option (although 225/50R17 isn't far behind). In the above chart, I haven't taken into account rim width, and because the 225/40R19 tyre size is normally fitted to a rather wide 8J rim on the Karoq, the difference is even bigger than shown when changing to a smaller rim diameter.
Compared to 225/40R19, 225/45R19 increases the gearing by 3.4% so the engine won't pull the gears so well. If you want more sidewall and more comfort, it's probably best to choose a smaller diameter rim size so that the outside diameter of the tyre is still about the same as standard.