Unfortunately many engineers (and humans generally) can't easily recognize and articulate what they need. One theory of mine is that we assign senior-sounding roles in this industry too readily. "Senior engineer" sounds like they would know how to handle this, but while they might be great at programming, they often have little experience recognizing their own limitations, asking for help/resources, and understanding that this level of self-awareness and focus on outcomes would make them look better, not worse.
If I was to give one piece of advice to an engineer in a similar position: you will always look more mature and professional if you evaluate your situation and explain what sort of help you need, than if you silently keep burning yourself out while the quality keeps slipping.
If you're management and you actually reprimand them for asking for help, you will have trouble retaining engineers. It would be justifiable for them to look for work elsewhere on these grounds.