As far as i can tell, there's nothing stopping him from getting things started right now in 2021. This year will go by very quickly, it is almost March. Next year will be the mid-terms, hopefully Trump can help oust all the ahole Rinos that voted to impeach him, as well as get rid of McConnel as well as the current chair of the Republican Party. I believe by starting now, the other Republicans such as Pence that may want to run for 2024 wont start campaigning until much later so he will have a very good head start on them all. My opinion 2024 is his for the taking. The only question is if he wants to go through everything he's been through again.