Well I can tell you my experience and the experience of coworkers since I am in the same boat.
Option 1: You just bare the expensive transaction fees. I guess you get free safe keeping so you will trade once every 2/3 months buy VT or VWRL and that is it. This is what I am doing. I know it’s not optimal but since trading is so expensive it’s also a deterrent to just leave things and to not play.
Option 2 Go with a robo advisory like Truewealth. Some of my coworkers do this as it’s rather simple and you can do monthly investments instead of the once a quarter. Run the numbers based on your savings rate and see which is more cost effective for you.
Option 3 You can get an exception from these rules in general only if you want to buy an instrument now available in your own bank, at least this is the rule in our compliance department. I also know of one coworker that has done this. Once you get the exception you can use the external account for other things too. For me personally it’s not worth the hassle.
As for mutual funds I don’t know of any provider offering this to Swiss clients. I know some Swiss banks have mutual funds but they are mostly CH based so not the most tax efficient funds outside your pension accounts.