Dumb beginners mistake. Need tips

Hey Bitcoin People

I made a stupid beginner's mistake. I started with Bitcoin back in 2021 before the crash happened. I then stopped investing during the crash, as befits a complete beginner. But I still put a little bit in here and there. My average buy in is currently worth 15k less than bitcoin.

Unfortunately I didn't buy my coins on a platform that allows you to transfer them to a cold wallet. Where I have my coins now I can only buy and sell which doesn't do much in the long run. After all, you want to own the coins.

Now the question is what is the best way to minimize losses? My idea was to sell 10% of my holdings every day and buy bitcoin again on a new platform so that I can transfer the coins to my cold wallet. I'm trying to use dca to make the highest profit on the sale

Unfortunately, the whole thing is accompanied by losses as I will now be buying at a higher price. But nobody can know when the next dip is and the halving is imminent.

Are there perhaps ways of making less of a loss? Unfortunately, as far as I know, there is no other way out of this situation. Unless Trade republic allows the transfer of bitcoin to cold wallets out of nowhere