That's how it's supposed to be. Unfortunately, that is not how it is right now. To even try to restore those states rights, will take the courts. And even if the courts are willing to do their jobs properly, the process would take years and we'd be lucky to see it resolved before the 2028 elections.
This is Trump's modus operandi. Fuck shit up and when the courts try to sort it out, drag things out as long as possible so that by the time a decision is made, you've already done whatever you wanted to do in the first place.
Bottom line. Don't vote by mail because your vote will not be counted that way.
Edit to clarify their plan:
When election officials bring ballots to their USPS site for delivery, either the entire batch of ballot envelopes or a sampling will be physically scanned – depending on where the ballots are being dropped, according to the whistleblower. If just a single ballot envelope scan does not align with the information in the portal, USPS will refuse to deliver the entire batch of ballots while the discrepancy is being sorted out.
When you request a ballot for mail in voting, election officials mail it to you. The USPS plan is the hold up ballots before they are delivered to voters. If even one ballot is addressed to a voter/address that doesn't exactly match the USPS list of allowed voters, then the whole batch will be held up until they sort out the error. That sorting out will not doubt not be completed in time for you to get your ballot and fill it out.