Sindome is a deep investment game and is kind of the mother of all sunk costs when it comes to character progression, but it is not an infinite well of gameplay and roleplay engagement that can last forever for everyone. You can, and eventually will, do everything you could reasonably do on one character, and the one thing time and resources and ue advancement cannot give you on any character is the experience of a different character and a new story to tell. There is no amount of wealth or power that can replicate a change of scenery, and I really think players get trapped in this purgatory of Did I Achieve Enough and Starting Over Wouldn't Matter Anyway where they will stop having fun and just stagnate trying to thread a needle that doesn't exist and will never exist.
Some players can get very hung up on the speedbump of having to go through UE advancement again but this is in my view a non-factor in these situations, anxiety about 'starting over' in UE terms is vastly more relevant with players who are still in the midst of their progression and fairly non-relevant to players who are years deep already at Max UE. At these points two years of development is much less relevant against the idea of the story of all those years coming to a final end. In this denial state players may spend years articulating all the arguments for why there should be shorter progression while playing careers that could have contained two or three max UE characters in their breadth. These discussions will be for some, essentially, procrastination.
The game cannot save you. Sometimes the story is just over. I would urge players who are struggling to find purpose or interest or fun in things to not be so precious about the page and kill their darlings.