I think you are conflating actual things with nonsense. Here is a brief reply that is unlikely to help.
1. In every transaction there is an equal amount of buyers and sellers.
2. In some transactions there is excessive demand, which can cause prices to rise. Likewise insufficient demand may cause prices to drop. The same is true with supply except the price action is reversed.
3. Do not confuse demand with buyers and supply with sellers; that’s like suggesting all girls are moms and all boys are dads.
I'll be honest I am approaching this from a DEX point of view, so what you say I'm sure is true for traditional markets and on that I will hold my hand up and say I'm wrong.
But on a Dex, using an automated market maker, I can buy an asset without requiring a seller on the other side of the trade.
The algorithm will adjust the price based on the liquidity of the pairs in the pool
More buy pressure price goes up, more sell pressure price goes down.
Uniswap is an automated liquidity protocol powered by a constant product formula
docs.uniswap.org