That aside you can make use of a good DEX and I'll recommend
exch.cx based on their reputation on this forum and I have also used them a few times too.
Also depending on how much your coins are, I suggest you use a different device to create a lightning channel and not the device you used for your cold storage.
Thanks, I will have a look to EXCH. But If I withdraw my USDT from a CEX to a DEX, I will be tracked too. That's the point. What's happened If one day I have to sell my BTC ? you never know what the future holds....As @ABCbits say, in France the want to freeze BTC from conjoins. (It is ,to yet but It will be soon).
For lightning channel I use Phoenix Wallet. It is a Hot wallet but I use fo small amounts to buy coffee or pay back friends...
My BTC long term will stay on my cold card.
DCA for nephews is on a Legder Wallet.