Our democracy is broken, and the people capable of fixing it are actively incentivized to keep it broken.
[1] https://www.miamiherald.com/news/politics-government/state-p...
The headline of that article is "If you vote by mail in Florida, it’s 10 times more likely that ballot won’t count". That's not equivalent to what you said.
If there's a 99% chance your vote will count and 1% chance it won't, a 10 times more likely to not count changes that to a 90% will count/10% won't count chance. Using your wording, it would change it to a 9% will count/91% won't count chance. Those are vastly different things.
Voter turnout is still not very high.
The envelopes have to remain sealed until they're brought into the room with the election monitors to be counted. If the seal isn't intact or the envelope isn't signed underneath or the bar code under the flap doesn't match the one on the ballot then the ballot is considered spoiled. The actual ballots are wrapped in a "secrecy sleeve" so that the votes can't be seen without unfolding them, and the election monitors separate the envelopes with the signatures from the ballots before they begin counting, so the secret ballot is preserved.
From that point forward they're processed just like any other paper ballots.
A couple of weeks before the midterms I'm going to get a packet in the mail containing my ballot, instructions for filling it out, a pamphlet where every candidate on the ballot gets a paragraph or two to make their case, and a prepaid return envelope. I fill out my ballot at my leisure, stuff it in the envelope, sign the envelope underneath the flap, and drop it in a mailbox. There's a receipt with an anonymous serial number in the packet that I can go online and use to verify my ballot has been received. If I'm worried about missing the deadline there are also dropboxes in most government buildings I can drop my ballot in up through the day of the election, along with a few traditional polling places open on election day.
Voter turnout here is about twelve points above the national average.