There's absolutely nothing to worry about. Simply zoom out to see the whole picture and expose the FUD:

Source:
BitinfochartsWe see that we have more transactions (~400k per day) than at any time in history, with the exception of the Ordinals/BRC-20 wave in 2023/24. Even if you look at the "all time" graph
here nothing changes, there were only two very short spikes in 2017 and 2019 where the amount of transactions came close to 400k too. But in 2020-22, most of the time there were less than 300k.
It's possible that Bitcoin's user growth rate doesn't fully translate into the growth rate of transactions, even if we look at second layers (Lightning activity continues to be slightly declining). And that would hint that indeed the share of "custodial" transactions is growing. Well, there's some work to be done for the community to install the "not your keys not your coins" principle in bigger user groups.