Becoming ever more obnoxious with ad placement because your ad-supported service is losing money and you don't know what else to do is a classic late-stage-enshittification step. It is usually the last one before the service becomes openly hostile to its users and partners and becomes a mostly-worthless relic. I did not think Youtube was at that stage or even close to it but maybe it is.
I can't really tell if Youtube is losing money or not, but it creates about $8 billion per quarter, and Google's overall operating expense is $55 billion per quarter, and I think it actually might be a safe assumption that Youtube is a pretty decent amount of that expense given its scale and its storage, bandwidth, and employee-resources requirements.