Selling pressure always gives a challenge to a market that is uptrending. Since it works in an opposite trend, selling pressure becomes a hurdle to beat by the uptrending market. If the demand pressure outweigh the selling pressure in a huge margin then I do not think that this selling pressure will hinder Bitcoin from reaching $100k.
Anyone will be tempted when they see that the price of bitcoin can reach the ATH, it could be said that the profit is already in hand and missing this moment is of course something that is difficult to avoid, when the price passes the ATH, which has happened of course the selling pressure is very large, making it difficult for the price to rise higher.
To reach the previous ATH it will take strong support from the investor and most of the time btc breaks its previous ATH with little effort. The sentiment became so bulish and the market created such FOMO that the market got more buyers than sellers. However most of those who bought btc at its previous ATH already sold their holdings or liquidated them through future contract or lowered their average buy through DCA. So i don't think this will be a problem to be concerned about.
The approval of ETF might help greatly since this will bring new funds to the market, making the demand grow. It will make it easier for Bitcoin to break ATH if FOMO appears but obviously FOMO often times has it backslash when the market sentiment stabilises making a huge correction in the market.