I’m still thinking of options how to widen the range, do it once to make sure I will have enough range.

Rohloff is not an option as it costs high and not accessible for me as a direct swap kit.

At this moment I ended up with Shimano hub and 11-36 cassette and while 36t will definitely be enough for me for climbs if 11t will not at some point I can change the chain wheel for something bigger like 54/56t.
y understand is that another option would be CS-RK3 which is direct drive at 2nd gear and will provide - %25 and + %33.3 to the cassette gear. It costs about $130 and is accessible to me. However it seems like it will accept max 9 speed cassette (11-34t) which means derailleur will also have to be changed. It will also add 1.15kg of weight. The question is which cassette does it accept, will it accept Shimano cassettes? As they are the most widely available in Istanbul.