But still, if you dump your altcoin right now, your profit will not be too big because almost the altcoins price is down a lot and it is waiting for the next bull run that can happen this year or next year.
Waiting for better times doesn't always end up well and more often than not you will end up with having less if you stick to altcoins, at least in the long run. Back in 2018 I decided to do something similar to what OP is doing; I sold all my alts except ETH and put everything into BTC which proved to be a great decision. Majority of them I sold with the loss, but I would be at even bigger loss now if I decided to wait.
Maybe that will work for some people, but we will have our own consideration to still hold or sell all of alt.
Maybe if you are not too late to sell your altcoin at a high price, that will be good for you as you can make a big profit and have bitcoin as your hold.
But I guess this time will be different than a few years ago since the bitcoin price increase so high and that can make altcoins will not get down too deep if the correction for bitcoin price comes.
The altcoin will have the chance to increase higher, so maybe that is why waiting can be a good solution for some people.