Hi, as this is an overlap of two topics - ETF/Investing and Taxes - I hope this is the right place, otherwise please move or delete it. I wrote a small summary of my understanding of the situation, feel free to skip to the questions in the end The way I see it, I am too poor for all of these articles
I am new in Switzerland as a foreigner making less than 120k/year, and as such I am subject to the horribly named - but quite advantageous - “Quellensteuer”. Horribly named because whenever I use google or this forums´ search for my topics regarding QS and ETFs I land on pages taking about withholding taxes for ETFs (L1W, L2W, etc). So excuse me if this question has been answered.
Please, for every assumption I make feel free to correct me if I’m wrong:
 As of 2021, there is no more way to retroactively lower your Quellensteuer by sending in all your possible tax deductions (etc. Pillar 3a, …) and still getting Quellensteuer-ed. To get these tax credits, you now need to do a “Nachträgliche Ordentliche Veranlagung”, which basically means getting treated like a Swiss person or Foreigner >120k/year and paying normal taxes.
Due to my combination of Kanton, County etc. this is way worse for me, even if I’d be able to deduct 10k CHF from my salary, I would still be better off just staying in Quellensteuer. (Its that good!!). Hence 3a is not an option for me, but thats not my question
 The age old question of US-based ETFs vs. Ireland-based ETFs. I will disregard:
- inheritance issues (I will stay below the CH-US treaties 11m for sure…)
- TER differences (0.08 vs 0.22 for VT vs VWRL, but lets go without this one for now)
So for taxes, if I read correctly, we are talking about:
- US based:
3% L1WT (0 for the US companies, non-zero for rest of the world, averages to ~3%)
15% L2WT, that I can (???, see below) get back through DA1
- IR based:
0% L2WT (yay tax treaties!)
So my big question is, can I claim DA-1 while staying in Quellensteuer? I have no plans to do a tax declaration, as it will lead to way more initial tax, so is there a way to just claim the L2WT for the US-based ETF straight from my Quellensteuer or would i need to do regular taxes? Because in that case I will just stick to the Irish one, as it is actually more advantageous after all.