Hello, so in my base I have around 10 villagers and maybe around 25 beds around in around 60blocks radius. I managed to breed around 4 baby villagers, but now when they make love the hearts icons suddenly change to those angry particles or whatever instead of a new baby, so what's wrong? Here I read that villagers need 3times as many beds as is their count +3 more to breed! That sounds weird, is it still true or was it a bug back then?
Don't think that's true, I believe it's just 1 bed per villager...plus 1 (for the baby). Prior to 1.14, when villages were determined via doors instead of beds, you needed a 3.0 to 1 or 3.5 to 1 ratio between doors and villagers (roughly 3 times as many doors as villagers).
Perhaps your beds are simply too far away for the villagers to find them? 1.16.2 made villager detection mechanics quite small, in order to mitigate free villagers all the way across town from claiming the workstation/bed that is nearest to some other villager (perhaps one you just brought in and are trying to get better trades with).
more and more mysteries. OK so you say the beds are not the issue. What about doors? I didn't think about that. Does their number matter? Now I have made several more beds in lower level and new babies were born and they claimed them! Still there are around 10 beds free though, but they are around 15-25blocks from the place where breeding succeeded :-] So I wonder if those might be too far for villagers to notice...
The only thing villagers need to make babies is an unoccupied bed and food. So, one extra bed more than the number of villagers. they have to be able to touch each other. and having at least one block above their head will help them to do their little 'dance'. I always give them a crap ton of bread. but they also will only produce a baby at a certain time of day. They all have schedules. https://minecraft.gamepedia.com/Villager#Schedules
If this doesn't help then having a bell around them might help or work stations of some kind? It might push them into their routine so they will breed.
Doors have nothing to do with the villagers any more. That was in the older Minecraft versions.