22y seeking investment advice

Hi,

I'm 22 years old, I live in NL but I'm originally from France. On my French bank account I have 100 000 ( parent died when I was young) and I have 40k sitting in a account with less than 1% interest. I wanted to open a PEA ( plan epargen action) where my french bank would basically place my money and it is very intresting in terms of taxation after 5 years but unfortunately you have to be a fiscal resident of France which I'm not anymore. I have looked into investing into ETF but idk through which platform, because I'm not sure if I will keep my dutch bank after my studies and through my french bank it is quite difficult ( their app/ website is not intuitive at all). I also looked at brokers platform such as Degiro or private investement company such as Robeco ( often they ask 10k minmum), but idk whats the best for my situation. Also I'm uncertain of how much I should invest as I might need to money in the future but that kind of investment is more long term. Any advice is welcome 🙂
Also at the moment I don't need to use any of the money saved because I work alongside my studies.

Main questions:
How much should I invest given my age and capital?
Where to invest, platform, private bank, bank?
Errors to avoid?