Rig vedic seers foresaw this type of doubts long back. That was why they stated that there is only ONE BRAHMAN, but might be called in different names by the knowledgeable persons.
Rig Veda I.164.46
इन्द्रं मित्रं वरुणमग्निमाहुरथो दिव्यः स सुपर्णो गरुत्मान | एकं सद
विप्रा बहुधा वदन्त्यग्निं यमं मातरिश्वानमाहुः ||
They call him Indra, Mitra, Varuṇa, Agni, and he is heavenly
nobly-winged Garutmān. To what is One, sages give many a title
they call it Agni, Yama, Mātariśvan.
Same mantra can be applied to the present day different deities, Shiva, Vishnu, Ganapati, Shakti, etc.