Thanks everyone for the answers, much obliged! Regarding the "clicking" sounds: to my ear that's how it sounds and from other videos on youtube it seems normal, but i do have to mention that i have some ear issues due to a past inner ear infection (made worse by some long covid issues) and my hearing is a bit messed-up (not up to standards to to speak). Well, now that i think of it that " high frequency modulation pulses" as Malcom mentioned is perhaps a better fit to the actual sounds.
That being said, i did manage to track 60 seconds at 300 mm focal range (450 effective focal ratio since my Nikon is a APC-S sensor). ISO was 1600. At 120 sec (and quite frequently at 90 sec) the stars become elongated (and although noticeable only at 100 resolution, i found it disappointing nevertheless). Obviously, still a far cry from 5 mins unguided; on cloudynights? some users managed that with modded HEQ5 but they were pro's whereas i am painfully new to the whole game . So, for me it is ok for now. Of course, i will go the guiding route once i familiarize myself properly with everything (it did take me 7 hours to take 120 60 sec exposures due to various user errors. Also had some equipment issues since i was using a 12V 14Ah battery which had to be changed in the middle of the session. Same went for the camera battery.
So, what was different from previous nights? First, i re-calibrated the polar scope during the day. My polar alignment through the polar scope was quite good (around 5 arcmins). Using the polar alignment routine in NINA i took it down to around 30 arcsecs but there was a lot of atmospheric turbulence (Romania is not the best country for imagers and especially not my location, so 'it only' took me about 1 hour to take it down from 5-6 arcmin to around 30 arcsec. Second, my Sigma lens was set on autofocus, i had to switch it to manual. Third, lens was set to stabilization on, should have been off. This was apparently a major issue that i kept ignoring (please don't ask why.... ). Fourth, i loosened the grub screws just enough on either side of the worm carriers but without introducing any backlash, so that might have helped too.
I should also mention that Sidereal vs King rate made no difference (M45 was exactly above me so from what i read it shouldn't have at that altitude). Setting drift compensation to 3 apparently did not seem to improve star elongation at 90 and/or 120 sec either. I will tinker some more, but for now i am satisfied. Perhaps in a month or so i will add another layer of complexity and will acquire the EvoGuide as a guide scope.