Oh man, this can be a tricky situation. I have been there and it can be very hard and really demoralizing. In many cases you CAN overcome it; in others, you may realize that the process will never properly incorporate user perspective and your work, and it may be time to consider other options. I've been there too.
Some of this may be purely relationship building, some may be the possibly painful but often necessary task of evangelizing and educating your development team - and possibly your product owners. Decisions should come from the product team, so if you can get them to prioritize time for research and up-front ideation/flows/wireframes/research/etc. BEFORE the development team has begun building things, it will make your collaborations easier and create a better product in the long run.
Some of it also may depend on the development team's process. Is your team working "waterfall," some flavor of Agile, Rapid, Lean, XP, something else? Not all of those play as nicely with design unless it is deliberately integrated into the process. Again, the product owner usually has to define and enforce the process and flow of work. If Engineering managers are part of that process - or the product owner is an engineer at heart - it can complicate things... in which case the education piece is critical.
I had a development team that not only barely knew we existed, but had no real idea what we did or why we could be useful to them. A colleague and I did a series of road-show short presentations about UX, why it matters, how we can help, and some things to keep in mind when we aren't around (because we had a ratio of like 80:1 eng:UX at that point). The basic points of the first two presentations are in the comments of these videos - the videos were meant to be entertaining ways to drive some of the points home (and yes, they are silly, but meant to make some of the details more memorable - it sort of worked):
Intro - Who we are and how we can help: https://vimeo.com/132271405
Design Principles - Gestalt: https://vimeo.com/132273309
Ok - I'm sure you know all this, but for any newbies out there: Ideally as new features/functions/updates come along, the product team prioritizes them - with your input for user perspective - then gives you and maybe an architect some time to work with them to define the requirements (business and user) for the thing, possibly with some research input. Then you and the product team work together to define how all of the controls, options, parameters, and data need to come together in a nice flow for the user to get the task done. Then wireframe out the flows based on your expert understanding and the team's guidance, and run it by some users to see if it makes sense. Iterate, redesign, and make sure the dev team is involved - they will help understand level of effort, system limitations that might affect your designs, etc. When things are deemed solid, mock it up (or possibly not if you have a component library), and get it over to the devs for building. Make sure to offer to work with engineering and be available for questions, and have them include you in demos. Try to partner with QA and have validation of the designs be a part of their process for vetting the engineering build.
Sometimes you will just be fighting against business priorities, which will almost always win. It is possible the business truly does not care about putting resources and effort towards improving their user experience - either because they don't really understand the benefits of putting time into a proper product design process (counter with evangelism and education); they might simply have larger priorities or immediate system limitations that mean they can't do what you know is best (make sure you have a backlog of issues that need fixing when time and system can accommodate them); or it's possible they are "X-washing," which is my term for when companies hire UX teams to say they are user focused, but they don't let them do any substantial work or ignore all of their recommendations that might cost them anything extra.
Good luck with this - it's the existential struggle for UX in a lot of cases, and you are not alone. Let me know if I can help any further, or just be part of your support group :-)