I need some advice here... This will be a long one, please bear with me.

First, some background:
I'm a senior level developer working in a company that primarily doesn't produce software like most fast paced companies. Lots of legacy code, old processes, etc. It's very slow and bureaucratic to say the least, and much of the management and lead engineering talent subscribes to the very old school way of managing projects (commit up front, fixed budget, deliver or else...), but they let us use agile to run our team, so long as we meet our commitments (!!). We are also largely populated by people who aren't really software engineers but who do software work, so being one myself I'm actually a fish out of water... Our lead engineer is one of these people who doesn't understand software engineering and is very types when it comes to managing a project.

That being said, we have this project we've been working for a while and we've been churning on it for the better part of two years - with multiple changes in mediocre contribution to development along the way (mainly due to development talent being hard to secure from other projects). The application hasn't really been given the chance to have its core architecture developed to be really robust and elegant, in favor of "just making things work" in order to satisfy fake deliverables to give the customer.

This has led us to have to settle for a rickety architecture and sloppy technical debt that we can't take the time to properly fix because it doesn't (in the mind of the lead engineer - who isn't a software engineer mind you) deliver visible value. He's constantly changing his mind on what he wants to see working and functional, he zones out during sprint planning, tries to work stories not on the sprint backlog on the side, and doesn't let our product owner do her job. He's holding us to commitments we made in January and he's not listening when the team says we don't think we can deliver on what's left by the end of the year. He thinks it's reasonable to expect us to deliver and he's brushing us off.

We have a functional product now, but it's not very useful yet and still has some usability issues. It's still missing features, which we're being put under pressure to get implemented (even half-assed) by the end of the year.

TL;DR
Should I stand up for what I know is the right way to write software and push for something more stable sometime next year or settle for a "patch job" that we *might* deliver that will most definitely be buggy and be harder to maintain going forward? I feel like I'm fighting an uphill battle in trying to write good quality code in lieu of faster results and I just can't get behind settling for crap just because.