That's nice, I can relate to that. I too have a few quite pleasant memories from back in the day. Besides all the things that appear magical as a kid (and really aren't), now looking back I'm willing to say there were some occasion where actual spirit/spirituality emerged. Not really because of the priest or the whole mass procedure and stuff.
Like you wrote, people were silently coming from everywhere, out of the dark, by foot, fighting through the snow, the cold and wind (winters were harsh back then!), gathering in this huge historic building merely made of stone. I remember one time, this was only one single time, they were handing out these tiny thin candles at the entrance and when all the people were cramped in, they turned off the (artificial) lights completely. (Imagine that today, with all the fucking safety regulations, let alone the covid bs..)
And yes there was a lot of darkness, but there was also this sea of tiny flames making up this massive warm glow illuminating the tall gothic ceiling. And it didn't matter who you were in real life, people were standing together, shoulder to shoulder in their thick anoraks, to fight the cold. One could see ones breath in the light of the candles. It was quite magical, something more than just the sum of its parts emerged. I'm not saying that's the reason, but to this day I'm deeply inspired when many people come together and actually manage to be quiet together. Maybe that's why I like churches (besides the architecture) or meditation halls etc. in general, people tend to shut up inside..
Anyway, I got carried away a little, sorry.