Fun fact: even without that miner who chose to forfeit his block reward, we would never reach 21 million because of the way halvings work.

We always drop the last significant bit in the number which is equivalent to halving the number but also rounding down to the nearest satoshi.

That means the total we could have ever mined was 20,999,999,999,9769,0000 satoshis.

See the proof:
https://nostrcheck.me/media/0d97beae567fcec9c6574f1c6ef6126ea969d4992c3198e51c0fac52c5274a14/bdf9d4690352c19f779e67a3af0681f6a22fe3cbcd5eeb171fabfcea5b935a63.webp