Hello good afternoon,

I have read a few books about Bitcoin, either about its philosophy, how it works or economics topics. But I still have some doubts:

For some weeks now I have been thinking about how is it that the date and time that a block has been mined is assigned. I mean, when a miner mines a block, my spider instinct tells me that the epoch time is sent to his peers with the block, but of course, if he sends it outside the block, it means that the peers are able to modify that epoch time, so it would not be possible. Then I have to suppose that the epoch time is inside of what the miner is mining, but now I have another problem, if it is inside, then the miner would have to be modifying the epoch time every second, and therefore, the hash is modified. That is why the miner would have to start from 0 in the nonce every second (and also other things that can be modified to have more combinations, such as OP_RETURN).

I have also seen that the blocks have the exact time in terms of hour, minutes and seconds, that's why I don't see possible that miners can modify the epoch time every 20 seconds or something like that. Also, if so there would have to be a margin of what epoch time would be accepted above or below the current one, which would entail knowing how long it takes for a block to fully propagate through the network, and more complexities.

For example, if I look in mempool[.]space at what time block 893254 was mined, I get that it was at 13:43:43, and if I run this on my bitcoin node:
(hash of block 893254).
I get exactly the same time, in epoch.

I would appreciate if some Bitcoin guru could clarify this doubt, thanks