I think it's very possible for Bitcoin to reach a new all-time high this year, as the year is still very long, so anything is possible.
Similarly, for altcoins, it's a good start to the year with recent gains, so I don't think this is the right time to sell. In fact, it would be better to hold onto our altcoin assets, as there's potential for their prices to rise even further.
I'll agree with you here. I think this is the time for accumulation instead of offloading our holdings. Selling altcoins might be a mistake at this time because the markets are bleeding right now and most of the coins are in red. We should try to hold until the markets revert back and show some positive movement. I would personally not sell my holdings because I am here for a long run but yes, I do understand that some people might be in a rush because of poor money management. They just can't afford holding for more time because it might ruin their financials over the year. This is the reason why we should properly plan our expenses and only invest if we have the money kept aside which is not of much use.
Bitcoins too will start showing positive momentum much sooner now. They are still dropping but this drop will come to a halt and eventually the markets will reverse. I would still keep adding to my positions with no intention to sell and would recommend the same to others especially those who have newly started their investment journey.