I'll start with the big picture: executive functions are very much both nature and nurture. While some people are certainly more inclined to strong EF skills, anyone can improve them, and nearly all people of at least average intelligence can learn them into the functional range. So whether you are just asynchronous, or normatively delayed in EF skills, there are concrete actions that you and your instructional environment can take to improve and develop your skills to the point where they are not an obstacle to your personal life goals. So no, you are not doomed.
(And even if you do need compensatory strategies all your life, that's not any different than all of the myopic people walking around with corrective lenses. We all use some kind of compensatory strategies--you just don't always see them, because, well, they compensate!)
Here's an anecdotal example: one of our children probably meets the neurocognitive criteria for ADHD, but would not be diagnosable because of the absence of pathology. (We never had DC formally evaluated--but this is my field, and I have a pretty good idea of what we would have found.) By absence of pathology, I mean that DC learned skills over the years that allow unimpeded access to the major life functions (within normal limits), even without requesting accommodations from instructional or vocational settings.
There were definitely moments along the way when parenting DC felt more labor-intensive, but we were able to pair explicit instruction in EF at home with careful selection of the educational environments DC was in. DC attended six years in two different very small private schools (the second three years was in a multigrade/multiage classroom), and then was homeschooled through high school graduation. The first three years DC was one year young for grade (early entered directly to first grade), and the second three years, two years young for nominal grade (grade skipped on the change in school), with additional subject acceleration (by year six of school, DC had grade eight content for most subjects, and algebra I for math), netting three to four years advanced vs age. Managing the EF expectations was helped in school by the multiage classroom (with a few same-age peers, which moderated expectations), and by the openness of the administration to my suggestions. Being young for grade also seems to have actually helped, as more than one teacher ascribed EF delays to DC's age, rather than some of the more pejorative ascriptions teachers sometimes make (e.g., effort, motivation, behavior), and consequently made more allowances than they might have otherwise.
At home, I spent a lot of time working with DC and scaffolding/modeling strategies for managing attention, inhibition (impulse control), and motor restlessness. At the same time, we stressed (as I do with all of my students with this profile), that there is nothing intrinsically less-than about an ADHD-like profile. As long as you understand your own profile, you are in a position to make choices that support your weaker areas, and allow your strengths to flourish.
When we went to homeschooling after the second school, it became even easier to adjust the environment so that both EF demands and academic instructional levels were matched to each child. DC also had a very educational experience with the first dual enrollment class, when, for the first time in four years, due dates actually meant something. It actually worked out well that this course was slightly below DC's true instructional level (quirks of the placement test at that particular college), as that left some space for focusing on the EF demands. Over the subsequent years of university, while most classes were not, a few were in DC's true zone of proximal development academically; those classes were particularly helpful in making the further development of EF skills meaningful. Participating in independent undergraduate research was also a plus, since those were good intersections of high-interest and high-EF-demand long-term projects.
And, to make a long story short, DC now has excellent self-regulatory and organizational skills, has completed a university degree, and is pursuing post-graduate studies. DC is still the same person, with the same tendencies to talk nonstop, seek stimulation, and flit from one task or topic to another, but now with the skills to manage them (and turn them to productive uses), rather than being controlled by one's own impulses.
