How can one buy very small amounts of BTC with anonymity?

I am new to this world, and please explain to me like I’m 5. For context, I'm in the second half of my 40s and my level of education is limited to high school. One detail that might count is that I live in the EUR zone.

My intention is for the next year to buy BTC worth 50 EUR a month while getting some practical experience along with some knowledge and re-evaluating after this time. I want to do it for my kid, for reasons that go beyond “some cushion money”. While I am not a very educated person, to put it mildly, I am getting anxious about some totalitarian tendencies that my old continent seems to have acquired. Some call me paranoid, so I decided to stop talking about it in real life, but I assure you that I don't use my aluminium foil for non-culinary reasons. While right now I live in the “civilised world”, I was born in an Eastern European dictatorship and I can still get a sour taste when, once in a while, I see different news about what should be regulated next.

But I digress. From my knowledge, there are two ways of keeping my privacy while acquiring BTC. The first one should be in person, with cash, but I don't know how safe it is because, well, paranoia again. The second option would be to use a Bitcoin ATM where I can pay with cash. But to pay about 20% over the market… for me it's outrageous. And yes, I know it's not a lot of money but for me, it counts.

I would like to thank you in advance for any answers and wish all the best to everyone.