Are you saving for retirement or buying property? Then start filling your 3rd pillar (Säule 3a) first because of the tax cut. Ideally in a low cost provider (viac/finpension), but the bank you already have probably has an offer too. It might be a bit more expensive than viac, but still much better than not investing. Stay away from 3rd pillar at insurance companies, they might be hard to cancel. Do yourself a favor and do this just for the tax cut.

If you max out the 3a, you can start of thinking investing elsewhere. IBKR is the cheapest to buy a US domiciled world ETF. But the UX is not super easy and you will have to fill all transactions manually in the tax report.

Neon with investments is another option I can recommend if you prefer a swiss company and a simple user interface. Fees are low if you set up a savings plan and pick one of the 0% ETFs