If you find it boring and distasteful to do, then probably you are not a fit for that particular project. It is fine to "power through" that kind of work from time to time, and try to learn whatever you can from the experience. But if I found myself doing hated work exclusively, I would request another project or if all else fails look for a different job. After all, that could be exactly the work that someone else would be happy to do. (Maintainer personalities exist.)
Another possibility is to push for a rewrite of the app. But sometimes businesses want to "drive it til the wheels fall off" to maximize the up-front investment. And often, full rewrites end up no better than the original... the technical debt just moves to a different place. You might find some success with proposing a progressive rewrite, if the application can support such a thing. Meaning, you do a new app but it is integrated into the old one. At first, it just takes over a small part of the old app's functionality. Then you progressively move more pieces over to the new app. This is easier to do on the web, considering the way HTML works, but could be really difficult in other scenarios.
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If you find it boring and distasteful to do, then probably you are not a fit for that particular project. It is fine to "power through" that kind of work from time to time, and try to learn whatever you can from the experience. But if I found myself doing hated work exclusively, I would request another project or if all else fails look for a different job. After all, that could be exactly the work that someone else would be happy to do. (Maintainer personalities exist.)
Another possibility is to push for a rewrite of the app. But sometimes businesses want to "drive it til the wheels fall off" to maximize the up-front investment. And often, full rewrites end up no better than the original... the technical debt just moves to a different place. You might find some success with proposing a progressive rewrite, if the application can support such a thing. Meaning, you do a new app but it is integrated into the old one. At first, it just takes over a small part of the old app's functionality. Then you progressively move more pieces over to the new app. This is easier to do on the web, considering the way HTML works, but could be really difficult in other scenarios.