BTC'ers "owning" coins: proportion of self-custody vs. custodial or owning "shares"

I am going to take some numbers put out by Dan Morehead, of Pantera Capital, as one of the starting points of this train of thought track.

The numbers (according to Dan):

"50 million people in the US own it, 300 million people globally."

On this very helpful site:

https://bitinfocharts.com/top-100-richest-bitcoin-addresses.html

Sum the 'Addresses' numbers to get to the total number of addresses holding funds on Bitcoin:

At the time of making this post, I get:

6071334+11203791+13090972+11597408+8023935+3504198+845569+134821+14640+1990+93+4 = 54488755

In other words about ~ 54.5M addresses.

So, by Dan's rough numbers (which I'm sure are smartly informed), these 54.5M addresses must cover ~ 50M + 300M = ~ 350M "owners of bitcoins" in the US + the rest of the world, combined.

Now, we know that self-custody is only possible if you hold your coins on at least one address.

So the total number of self-custodial holders can at most be 54.5M, in fact it'll be appreciably lower because few people have only one address - as you transact using your own wallet, it usually generates multiple addresses for things like change or receiving amounts from people making payments to you.

But due to the "at most" limiting factor above, we can conclude that, if the "ownership numbers" are serious and relate to people actually owning bitcoins by either self-custody or in custody of others (like professional custodial services), then -

Only about ~ 15% of owners are keeping their coins in self custody.

That would imply about 6 in every 7 users are entrusting their coins to someone else.

This does not shock me, given the pivot in Bitcoin's official narrative to "store of value" and multi-front efforts to promote keeping bitcoins in the custody of financial institutions (*), for whatever reasons (safekeeping, lending against fiat or other coins, speculation etc).

Since this post is meant to be a discussion:

I am looking for data that corroborates or counters the numbers put out by Dan, to get a feel for how accurate the proportion is.

The blockchain data alone doesn't tell us this, since one person can and often does have multiple addresses, and some addresses, e.g. some exchange addresses or cold storage vaults, are also technically shared by multiple "owners" of the coins, although this is at best reflected by legal agreements and not enforceable on chain as many of owners have experienced when exchanges or (neo)banks went bust.

(*) "While the system works well enough for most transactions, it still suffers from the inherent weaknesses of the trust based model." - Satoshi Nakamoto