Hi, I'm new to 3D simulations, so this question might sound foolish, I was wondering does particle count affect the final render's quality ? Like when I'm doing flip fluid simulations I can see low particle counts give less details and when I create more particles it gives high details, is this same with final rendered output ? Do I need to sim with higher particle counts before final render ?

You pretty much described it exactly. Fewer particles will give less detail and a less accurate simulation. More particles will give more detail and a more accurate simulation. Beyond some point, adding more particles won't make a noticeable difference in quality, and at that point, you can stop adding particles.

If the particles are being surfaced decently before rendering, as long as the fluid sim results are what you want, you probably don't need to re-sim for final rendering. (That said, I'm definitely not an expert on fluid sims; I'm just going based on second-hand information, so I could be wrong.)