Programs Management Analytics & Technologies UI Software Engineer interview questions

Probably THE WORST interview experience I have had. The last title I held was Senior Frontend Software Engineer. This is all clearly shown on my resume. With about 8 previous jobs I've held. I know this field is pretty goofy in how they judge these levels of experience but I do know im far from a junior. I worked within teams where I was asked to be a tech lead and mentored other senior software engineers and juniors. I should be Senior level by now. I had an initial phone screen with an internal recruiter who says the position is Midlevel, though the Job Description said Minimum Experience Level -> MidLevel so that tells me they will take senior level too. I gave a senior level salary range when I was asked. I was scheduled an Interview for the position, spoke about Frontend, UI, React.js, Micro frontends, SDLC, Unit Testing. I was given a take home test to build a Backend API that matches the skills of the Jr. Software Engineer position, not the position I applied to. Not sure what is going on there, I assume they want 2 people in one. They should just call it a full stack position. I build this project like a senior would. I spent 70-80 hours, I went above and beyond, I definitely did not build it the same way I built projects my first few years. I get a text message from the same internal recruiter asking me if I want to schedule an interview for a Junior SWE? I just interviewed for what I thought was a UI SWE (Minimum Mid Level) a week ago. I was told that that is the only interview in the process. Are they determining my code is Junior Level? I am so confused. I continuously improve every day. I no longer write code the way I used to. I am far more experienced, I know I can always learn more, but 8 years, im not a junior. It feels like a slap in my face. I have never seen a Senior developer go backwards. I feel like im being lowballed in some way.