In addition to that, what do you think is beyond observable universe? Probably more of the same, possibly infinitely more. There is no good reason to think that universe suddenly ends at our local "bubble", and we are in the perfect center of it. So the number of atoms is potentially infinitely larger than what we can observe (not that it matters, as the whole calculation is flawed anyway).

Lies, Damned Lies, Statistics, and Probability of Abiogenesis Calculations:

If you want the size for a specific transaction, you could calculate it here: https://bitcoinops.org/en/tools/calc-size/

For a 1 to 1 taproot tx, it would be 111vBytes

Halving: https://github.com/bitcoin/bitcoin/blob/4c57e53a61e6ae65ee87a25b1355530224b5ae9e/src/validation.cpp#L1551

Dollar amounts are for the average native segwit transaction of 140 vBytes (you can see explanation if you hover over it on desktop).