I have a Kona Rove ST (specifications here).
I'd like to change the drop bars by flat bars (it will be better for the travelling I'm planning, but that's not the point). But I don't know what shifters I should take (if only there are some compatible, but I'd guess so).
I'm not that concerned by the weight, so I prefer the cheapest of the shifters if the only difference is the weight.
The Kona Rove model you referenced has SRAM Rival 1x11. What you would need is an 11 speed rear shifter that uses the same derailleur actuation ratio as the drop bar shifter.
Actuation ratio is the ratio between cable length pulled per shift and the lateral movement of the derailleur cage. To get the derailleur to index on all sprockets correctly the cable length pulled multiplied by the actuation ratio must equal the sprocket center-center spacing.
SRAM gives names to the different actuation ratios they use SRAM Rival 1 used 'Exact Actuation' which means the ratio is 1:1.
As far as I know all the SRAM MTB systems use 'X-Actuation' which is not compatible with 'Exact Actuation', so none of those shifters will work.
SRAM makes road specific flat bar shifters. The page does not specify the actuation, but does say that the shifters are compatible with 11 speed rear derailleurs.
The SRAM Road Compatibility Document is a somewhat hard to interpret but I believe it says that these shifters are compatible with Rival 1x11 rear derailleurs. Look for the 'x11 Road Compatibility' page, note 'S-500' series is listed in the rear shifter box.
