Background
I have been in my current position as UX / UI designer at an in-house insurance design agency for just over a year. Prior to my arrival my line manager, who is a designer himself handled this aspect of the agency's work.
People really like my work, mostly on the UI side (As I don't have much time for proper UX work, like testing), I have developed an in-house design system and standardized 10+ products while working closely with developers to ensure good implementation. Clients are universally happy with the work and say their workflows have improved dramatically.
The Issue
However, I find myself becoming overwhelmed by a growing number of stakeholders and requests. Since BAs, Clients, and Developers from past projects require continuous support, I find its becoming harder to concentrate for longer periods of time due to frequent interruptions to deal with 'urgent' issues.
The key issue for me is continuing to deliver high-quality work for a large range of clients, while my schedule keeps getting highjacked by unexpected requests. Since these requests usually come from senior stakeholders, my line manager asks me to address them first, since "They'll only take 15 min". Not really considering switching costs or the fact that these tasks usually take at least 2 hours.
For example
A Project manager may come to me with a request to change an illustration for a login background on our most important project to incorporate elements of the Singapore skyline (since the product is being rolled out there).
The request will usually originate from an off-the-cuff remark from the CEO during one of the weekly demos.
I will usually make the PM aware of the fact that I have a high workload with other deadlines being missed if his request is done first. He will then go to my Line Manager, who will come to me with the request asking to spend 15 min.
After I spend the minimum amount of time necessary to complete the request, my line manager will typically expand the brief or increase the complexity in order to "Push me to do my best work" (even if the original PM and client are happy with the results). After I implement his feedback I am forced to spend an entire afternoon iterating on the design, eventually missing my deadlines.
Attempted solutions
I have raised this issue with my line manager, telling him that I am unable to manage my current workload. His suggested solution was to begin outsourcing some work to our supplier in India. But beyond the fact that the supplier's work is generally of low quality, he has so far not sent through any design briefs to them (as he is too busy) despite numerous reminders and my having done a decent draft brief as well as created an easy to use a template and a guide to the design system.
I have also informed all my other stakeholders of increased workload, and asked them to hold back any unnecessary work.
Final Thoughts
Overall since joining I have noticed that the organization seems much more chaotic compared to my previous employers (generally large tech companies). It seems the leadership is pushing the company to deliver multiple large projects (beyond our capacity) in the hope that one of them will be successful. But of course, the result is software that lacks key features and doesn't meet end-user expectations.
Due to a lack of focus, there is a very reactive culture among BAs and PMs.
My line manager seems to have poor time management skills and is not willing to accept trade-offs.
I am open to any suggestions, as currently, my plan is to quit after the bonus end of the year.
Apologies for the long post, but I felt the detail was necessary.