Raganuga bhakti is not for super humane beings with perfectly pure hearts.

It is a sadhana, a practice which starts and leads to an end: svarupa siddhi, the realization and perfection of your bestowed spiritual form.

vaidhi raganuga ceti sa dvidha sadhanabhidha
(BRS 1.2.5)

“Practice is of two kinds, namely vaidhi and raganuga.”

The moment the desire in your heart arises to serve Sri Sri Radha Mohan in Sri Vrindavana, the start of your raganuga bhakti journey begins.

To attain the Divine Couple in the nikunjas of Vraja, raganuga bhakti is the only way.

raga-bhaktye vraje svayam-bhagavane paya ||
(Caitanya Caritamrita 2.24.85)

“Through raga-bhakti, one will attain the Lord Himself in Vraja.”

raganuga-marge tanre bhaje yei jana |
sei-jana paya vraje vrajendra-nandana ||
(Caitanya Caritamrita 2.8.221)

“He who worships on the path of raganuga will attain Vrajendranandana (Sri Krishna) in Vraja.”

This desire is caused by the mercy of Sri Krishna and His devotees.

Srila Rupa Goswamipada confirms this in his Bhakti Rasamrita Sindhu where he states the ultimate cause for starting raganuga bhakti.

krsna-tad-bhakta-karunya-matra-labhaika-hetuka
pusti-margataya kaiscid iyam raganugocyate
|| BRS 1.2.309 ||

“The mercy of Krsna and His devotees is the only cause of attaining raganuga-bhakti. Some call this type of devotion pusti-marga.”