I have an old (early 2000's) Specialized Allez road bike that I want to convert to a hybrid (flat or raised bars) that is geared for hill climbing (super hilly city). It currently has Shimano 105 front/rear derailleurs with triple front chainrings. The rear derailleur is long cage. The rear cassette is 9-speed Shimano HG. The current low gear combo is front 30T, rear 25T... I want this bike to feel more like my old hardrock MTB which has front 24T, rear 28T- it seems like a minor difference but the feeling of the 24/28 MTB combo is totally effortless on super steep hills vs the 30/25 on the road bike..

If I keep the derailleurs what are good compatible "flat bar" index shifters to look for?

I see current 9-speed Shimano HG cassettes (CS-HG900-9) with a 12-36T option. If I just swapped to that cassette- would the front 30 / rear 36 feel similar to the front 24 / rear 28 MTB? Or should I also look for a smaller front gear?

And if so- maybe I could just find a smaller gear for my 74mm BCD crank.

What do you think?