Is it a red flag for a company to ignore a question about salary?

I applied to a job that did not post the pay range.

When they emailed me Thursday to set up an interview for Monday, they asked when I was available and what my salary expectations were. I told them my availability as well as salary expectations, but realized well into Friday I hadn’t received a reply. Worried that the business would be closed on the weekend and I would not hear anything until Monday, the day of the interview and potentially seeing the email too late, I sent a follow up email asking for an update on the exact interview time as well as if my salary expectations were in the range for this job.

They never replied on Friday, so I began to worry I was asking for too much and they were just going to ignore me, but did reply on Saturday to set up the exact time however, completely ignored the salary range question.

Is this a red flag? I just feel like if it was way more than they would pay, maybe they would say something instead of wasting our time. But I am still worried if it is not within the range they are willing to pay, maybe they’re going to try to offer me the job for way less just to see if I’ll take it.