I think I will sell everything I have (btc and alts) in the end of december, to USDT.
1) transfer it (usdt) on Tron on my ledger
2) Wait months
3) Wait again
4) buy back when bloodbath looks over
5) triple my holdings
Main question about my plan is it safe or not keeping usdt for months?
Your plan seems good and TBH, I'm thinking of that strategy too when the bear market comes.
The question is will 2022 be the start of the bear market and you are selling all of your coins and hold USDT? Because if the opposite happens and it continues to go upwards then you will incur losses in your portfolio.
There is nothing wrong keeping USDT for months. There is this risk of getting potential gains when you held BTC and ALTS rather than holding USDT and worse if it didn't go the way you like then you will get losses. Its better if you will just convert a percentage of it into Fiat, wait and then buy when you feel that it is low than converting it to USDT. Keep a percentage of your holdings too to hold BTC and ALTS just incase they will go higher then you'd still gain profits.
Diversifying your investment is very important, which will minimize the risk.
Be smart and be realistic all the time as a bullish market does not exist forever, just like our experience in the past, we have a bear market and bull market, so it's just a matter of timing and we have to do the right timing if we want to be successful in trading and investing. Of course, no one can predict the right outcome all the time, but with proper research and learning from our experience, it's not impossible to be consistent in trading.