Beginners should avoid short term trading with any coin (not just bitcoin). The safest and the most conservative method for you is to buy bitcoin at the bottom low value and hold it towards peak value. This takes a rather long time but your profit is guaranteed and losses are minimal.
Assuming you stopped at just avoiding short term trades with bitcoin, that I would had agreed to and considered a perfect advice but you saying same strategy should be deployed with other coins, that's a suicide mission that'll must likely end you bankrupt. Altcoins naturally are to be short when the profits comes in.
No doubt some specific project does very well long term but majority are always advisable you take out profit when ever that opportunity presents itself. Lets flash back to few months ago when the whole community was been disturb with defi madness, you cashing out that moment would had made you more profit than waiting to cash out my now.
The whole hype has died off or slowly dying and soon we might have shit dead coin all over the market just as the 2017 bullrun produced countless amount of worthless coins.