I would be careful in presuming that anyone starting in bitcoin needs to actually hold his own bitcoin in the beginning. Sure holding bitcoin is important and learning that holding bitcoin is what distinguishes it from other assets, but at the same time, I think that I a person (a beginner) can work up to holding his own keys and he might spend his first one or two years in bitcoin just building up price exposure and maybe learning about how to hold his own keys, and so people can be in different places in terms of how much they are able to learn at one time and how long it might take them to get to a point of being able to hold their own keys.. so I don't see anything wrong with beginners starting out with mere price exposure and realizing that they are not really owning bitcoin even though they are starting out by investing in price exposure and perhaps otherwise getting their finances and psychology in order so that they can continue to learn about bitcoin while investing into it (in a price exposure way)..
Yes, the more empowering aspect of bitcoin comes from having it (at least a decent amount of your BTC holdings) in your own possession, yet there are a lot of folks who have BTC in their possession, but also keeps some on exchanges and through third-parties too.. and so it is up to each person regarding the proportions of such and to realize the power of holding decent amount of BTC yourself... because none of us really can know when third parties, governments or even hackers might end up gaining access to coins that we are not holding in our own possession.. and yeah, hackers are getting more sophisticated too.. so anyone holding their own coins have to be careful not to get socially engineered or otherwise tricked or forced out of their coins.. which is also an ever changing topic and even very smart folks, long time bitcoiners might not realize some of their own self-custody vulnerabilities, even though it remains preferable to have a decent amount of self-custody when it comes to BTC.. but not necessarily telling everyone that you know.
Your points are clear to me. It is true that in reality beginners can benefit from price exposure to Bitcoin before they think of going into self-custody. However, knowing the investment with strong confidence is a crucial step if they want to be successful. Meanwhile, there are things to consider that could create balance. Individual risk tolerance and patience are some things to consider along the line but first they should be aware that exchanges can be hacked or restricted which so many person have fallen victim to such things. This should be the first thing when they get to the level of choosing an exchange to buy from and a wallet to store.
The solution to self-custody vulnerability is technical knowledge (strong password and hardware, seed phrase safeguarding, awareness of social engineering, and manipulation to mention a few). If am wrong please correct me. In as much as self-custody is the best it comes with responsibility which we would all account for ourselves, we should always think about it if it is the right approach at the beginning stage.