How much should I expect with a warranty issue from a large retailer/distributor?

I have a "new" Rose HiFi 150b, that I love, but it has technical issue. The XLR outputs produce a softer/duller/quieter sound on the left channel.

I noticed the issue as soon as I received my new amp with XLR inputs, with XLR-out being a primary reason I picked the 150B. I could not afford to get the new amp until 4 months later, then spent 2.5 months pin-pointing the issue to the 150b.

So, by the time I called the retailer, it was outside of their 90-day replacement window, so I got sent to the distributor. The distributor wants me to send the unit across the country (NC to NV), at my expense, and then they will fix and return, at their expense. They state they may or may not have the parts in stock.

I feel strongly that the XLR-out issue was there from the very beginning and desire the unit to be replaced. Am I expecting too much? Bullet points below provide more background:

• Purchased the unit from Crutchfield. Best price + I live in NC mountains, so no opportunity to buy local.
• MoFi is the US distributor of Rose HiFi, so I am dealing with them on the repair/return.
• Talked to Rose HiFi, their high-level techs agree the "audio board" is defective, apologized multiple times, but their hands are tied - sent me to MoFi.
• Crutchfield will only replace in first 90 days, they sent me to MoFi.
• I really do not want to send a new-ish $4,500 piece of delicate kit on two cross country bumpy rides. Ouch!
• I asked MoFi if they could send me an "Audio board" and I would pay a local tech to install it. Rose-HiFi’s suggestion. MoFi ignored this idea.
• Crutchfield has an "open box" unit on their outlet website, asked if I could trade for that; they didn’t much listen to that.
• Again, as soon as I got the new amp with XLR inputs (Accuphase E-380, new), the problem was apparent. RCA works fine. I am CONFIDENT the XLR outputs were broken when brand new.
• I have escalated with Crutchfield, the nice front-line tech support person I spoke with said he would talk to their "merchandising" team to see if there was anything else they could do. Waiting patiently.

So, do I just need to box it up, pay $100 shipping, and wait a month as MoFi suggests? Or do I dig-in and try to get Crutchfield, MoFi, Rose HiFi to replace? If I dig-in, what is best approach, and with who? Or maybe I am expecting too much?

I hope I have not learned an expensive lesson in dealing with an Internet retailer, like Crutchfield? Maybe they will step-up. Will report back either way.