A possibility to me is finding a means to avert that weakness of the Ottoman Empire that coincided with the French Revolution, as this would enable the Empire to start adjusting immediately and proactively when France is busy trying to blob all of Europe into itself. If the first steps to a new Tanzimat start in the early 19th Century, this makes the reforms both deeper and more solid in the long term, IMHO. The later the Ottomans wait, the more problematic their overall situation. OTOH nationalism is going to be a major weakness as Russia or whoever wants to hurt the Empire can turn a tax rebellion into a nationalist popular uprising and start carving their Empire up regardless.