Not believing in Gambler’s Fallacy is already believing there will be more “20 in a row same side than 21 in a row same side” - its believing there are 50% more

Not believing in Gambler’s Fallacy is already believing there will be more “20 in a row same side than 21 in a row same side” - its believing there are 50% more in a way. After the 20 have landed the next flip will still be 50/50. Just as 20 perfectly alternating heads/tails/heads/tails will lead to another 50/50 chance, or any other potential pattern the past may have held.