You are right to research these matters before you move to Ireland rather than after.
It's not the case that all ETFs are taxed at 41% and subject to deemed disposal.
You (or preferably a tax professional) have to examine the prospectus of the ETF to discern its structure as it could be the case that it is an ETF that can be taxed under general tax principles (income tax on income, capital gains tax on gains, no deemed disposal provisions), rather than under the 41% + deemed disposal regime.
If your particular chosen ETFs are eligible to be taxed under general tax principles, then your non-domicile status should allow you to benefit from the remittance basis of taxation. ETFs that are subject to the 41% rate and deemed disposal provisions cannot avail of the remittance basis of taxation and taxes would apply even if there was no remittance to Ireland.
As a non-domicile, you should definitely seek out tax advice in Ireland (and SA) prior to your move as there are practical matters to consider prior to taking up Irish residence i.e.
- identifying capital accumulated prior to becoming Irish tax resident and placing this capital in a separate account;
- ensure that any income paid on the capital is credited to a separate account so that remittances can be made to Ireland from the capital account, free of tax;
- review of investment portfolios to consider whether it is worthwhile to rebase investments;
- gifting assets prior to becoming Irish tax resident (though you do have a 5-yr window of time to play with here as a non-domicile).