MacBook Pro fans running on startup

I'm using a 15-inch MacBook Pro from 2015. The model number is MJLT2. I'm not sure if what I'm experiencing is a problem or not. I cleaned the fans and re-apply the thermal, it was all done by a professional 3rd party service center because the official service center in my city temporarily closed and usually takes a minimum a month to get anything done.

On startup, the fans spin is completely audible even from 2 meters. The fans are spinning not in their maximum speed but audible. It lasted for around 30 seconds to 1 minute, and then it turned down. Is this normal?

I also use FL Studio 20 running natively on macOS to produce music. I have been paying attention and the fans started being audible when I started on a song and that concerns me because a 15-inch MacBook Pro 2017 (MPTT2) is acting quite differently. I'm fully aware that it's 2 different laptops from different generations, what makes them similar are the processor speed. Since music production only takes advantage of the processor and not the GPU, I only do CPU testing between the 2.

On the 2017 MBP, I was able to play the same project without the fans blowing out on full speed, it only runs at 3500 to 4500 rpm. Meanwhile, I didn't find any performance drop compared to the 2017 in the 2015 MPB, instead the fans ran at full speed, which is really loud.

I'd like to emphasize working on FL Studio if anybody knows about this, but I'd like to focus more on the general thing and startup.

Thanks!