If only newbies will be willing to listen to your advice then they will not have a problem but majority of them will decide to ignore all this advice and do what they believe is the right thing to do but they will regret making that decision since they do not have any experience yet. It is only the newbies that listen to the advice from the experience investors that are going to make profit in the market for those that refuse to listen are going to make losses. Instead of FOMO it is better newbies buy Bitcoin and hold like you said but still many newbies will think that the best way to invest in Bitcoin is to buy when the market is high but what they refuse to understand is that that is when people are selling instead of buying.
It's not about newbies or experts, nor is it about buying at higher prices, but it's all about patience and holding on to the assets you have already bought if the market isn't favourable at the moment. The ones who lose are the ones who sell at a loss, that's what we all know about this market or any financial market in general.
You might buy at a higher price, because someone has to buy for another to sell, so it's not like no one would buy Bitcoin when it reaches $200k, but it's just that those who enter the market that late, will have to wait for the market to get their investments into profit, and meanwhile, all they need to do is stay patient and keep holding, or even better, keep adding more when the price is low.
The reason why newbies mostly lose money is because they easily become impatient and think that they are losing money when they see their portfolio losing value, which is not true, because unrealized loss is not loss until it becomes realized loss, and an investment in Bitcoin will only get you realized loss if you sell it lower than where you had bought it. If you stay patient and keep holding, those unrealized losses will turn into unrealized profits in the future, but at the end of the day, as I said, it's all a game of patience and self-control.