As odd as it may seem, it could be advantageous for the Democrats if Trump were to announce his candidacy for the presidency as soon as possible, and here's why:
Public polling has consistently shown him struggling to break 45 percent approval across the country, while internal GOP polling this year has found support for his candidacy hovering around 40 percent. His toxic brand continues to turn off voters in the suburbs, according to strategists in battleground states. He faces a litany of other headaches, including investigations into his businesses in New York, and a probe into his role in the deadly Jan. 6 Capitol insurrection.
It is not much of a stretch to say either the January 6 investigation or the lawsuit in Georgia (or both) could result in prison time for him - and you can't run for office if you are in prison. It's also possible that the investigation in New York could lead to prison time. Remember Leona Helmsley?
After allegations of non-payment were made by contractors hired to improve Helmsley's Connecticut home, she was investigated and convicted of federal income tax evasion and other crimes in 1989. Although having initially received a sentence of sixteen years, she was required to serve only nineteen months in prison and two months under house arrest. During the trial, a former housekeeper testified that she had heard Helmsley say: "We don't pay taxes; only the little people pay taxes", a quote which was identified with her for the rest of her life.
https://en.wikipedia.org/wiki/Leona_Helmsley
If he announced his candidacy before the 2022 midterms, he'll hurt GOP candidates who are aligned with his views (think David Perdue , Roy Moore, Kelly Loeffler, and Larry Elder).
“He has a deep and committed loyal base,” said Bob Vander Plaats, CEO of the Family Leader, an Iowa-based Christian group that has been hosting potential candidates. “But even in that deep and committed loyal base, there are many who don’t think Trump should run again.”
Trump’s fundraising efforts have persisted at a frantic pace, even though most of his direct appeals for independent PACs or his own cannot be used for a future presidential campaign because of how they were established under campaign finance law.
Trump remains focused on revenge against those who opposed his efforts to overturn the 2020 election results. He has asked David Perdue, the former Georgia senator, to run against Republican Gov. Brian Kemp in Georgia, according to people familiar with the matter.
https://www.washingtonpost.com/politics/trump-2024-campaign-candidacy/2021/10/03/73af3b12-21f8-11ec-b3d6-8cdebe60d3e2_story.html
If the Democrats can manage to get some of their legislative goals done, it's always possible that they could invoke the 25th amendment. At this point, though, that ploy would backfire on them since it would generate sympathy for Trump.