Contrary to what you think. Modi & Shah are more committed to the core Sangh ideology than say Advani or Vajpayee were. Enacting the CAA isn't going to get them votes in their millions except for a section in Assam & WB. Similarly implementing the NRC is going to get them a lot of brickbats. Yet they will be implemented not only because it's needed in any modern nation state but also coz it's an article of faith with them. Don't mix this up with electoral politics.
As regards Delhi since the days of Madanlal Khurana & SS Verma, Delhi BJP was consumed by infighting. Hence towards the end of the BJP's term in office, Sushma Swaraj was bought in as a compromise candidate. She was unable to stem the rot & INC under Sheila Dixit ruled for 15 years. Since the loss of both Khurana & Verma, BJP hasn't been able to put up a leader who'd be acceptable to Delhi. Hence you had Kiran Bedi the last time & now Manoj Tiwari. Finally, any amount of money thrown , nukkad sabhas, campaigning by all the top brass can't make up for honest hard work at the grass roots level with a trust worthy & acceptable face at the top of Delhi BJP. I'm sure there were many who'd have considered the BJP but in the absence of these factors preferred voting for AAP. The BJP would have to realise that if it means business they ought to get committed party workers who toil day & night in order to build their narrative from today and not when the dates of the next elections are announced. Its easier said than done though.
Funny part is Congress basking in AAPs moment of glory going by their statements in the media & on SM . An outsider could be forgiven for thinking the Congress has won The elections .The GOP has truly reached rock bottom and seems to be rather enjoying it's stay there.