Reset VT value with a sale in preparation for moving country

Hello, I have ~350k USD invested in VT and I would like to reset my gains to 0, in preparation of potentially moving next year to another country where there is capital gain tax.

I never sold a single stock/ETF since I started investing 5 years ago, so I am a bit panicking about how to do it.

I use IBKR and was wondering if anyone ever sold such large sums and what is the correct way/steps to approach the sale + rebuy to minimise fee and losses.

My understanding would be:

• Monday at opening of US market for higher transaction volume

• Set a limit order for the sale in between ask/bid

• Wait for the entire order to be fulfilled

  • what if only part of the order is fulfilled

• Set a limit order for the buy

Furthermore, since I need to retire using EUR, I was wondering whether I should continue using VT or using this sale to switch to an EUR based ETF?