Raam'Krishn' vs. Ramakrishna
Shri RaamKrishn (1836–1886) was born in undivided Bengal, and Bengalis called him Thaakur RaamKrishno.
Shri RaamKrishn never adopted himself the spelling Ramakrishna for his name. If he had himself done it so, we would have certainly respected his personal wish, and followed that spelling everywhere.
Since it was not by his personal choice, but imposed by others, we can re-examine it.
If you would want to pronounce it, looking at the spelling Raam'Krishn', you are likely to come closer to how it is written and pronounced in Sanskrit, using its original DevNaagri script रामकृष्ण.
You may, however, choose to look at the spelling Ramakrishna, and practice pronouncing it with the wrong accent रामाकृष्णा. The choice would be entirely yours.
I would, nevertheless, want to remind you that it is not necessary that a wrong practice, howsoever popular, must be followed, simply because others have done it.
Someday, I only hope that Ramakrishna Mission will find the desire strong enough to restore its true name RaamKrishn Mission. However, I suspect that, for doing this, they might need yet another Naren of present generation!