daivam — in worshiping the demigods; eva — like this; apare — some others; yajñam — sacrifices; yoginaḥ — mystics; paryupāsate — worship perfectly; brahma — of the Absolute Truth; agnau — in the fire; apare — others; yajñam — sacrifice; yajñena — by sacrifice; eva — thus; upajuhvati — offer.
Some yogīs perfectly worship the demigods by offering different sacrifices to them, and some offer sacrifices in the fire of the Supreme Brahman.
yajnea-aivopa-ajuhvati -> they offer themselves to Brahman, they offer soul into brahman, i.e. they conceptualise that Brahman is the absolute truth and I have to merge into that. That is also a kind of sacrifice where they offer themselves.
So the point is there are different kinds of sacrifices. So here Krishna is giving vision that how various religious activities in vedic culture are different kind of Yajna.
After describing these various types of Yajna, Shri Krishna will describe purpose and recommend Arjuna what he should do.
Srila Prabhupad's Purport: Those who are interested in material benefit worship the demigods by various sacrifices according to the Vedic rituals. They are called bahv-īśvara-vādī, or believers in many gods.
Bhau-isvara-vadi is called polytheism – how there can be many supreme? – different gods are having charge of different departments – they are under one Supreme God -> this is multi-level monotheism. Christians believe there are false god and true god and that is the reason when they would conquer some territory they will destroy all god worship there thinking that it is false god, but vedic understanding is that there are subordinate gods, there are assistant of Supreme God.