If you are talking about spreadsheet to estimate costs of investing in NEON / IBKR / Swissquote, then it is at this post
If you are going to sell ETFs in one shot with such large amounts, then yes IBKR or Swissquote would be cheaper because they have flat fees options. NEON does not have flat fees, so it would be 500 CHF + duties as you estimated already.
I do not know the answer about portfolio performance as I dont use it.