If there is a different trajectory to the Russian Civil War in 1919 or an effective anti-Bolshevik coup by the Kornilov revolt in autumn 1917 prevents the October Revolution occurring, we could see a long-lasting military dictator at the head of an autocracy in Russia after that date. Given the strength and relative coherence of the Russian military (and its popular reputation as a stronghold of national patriotic tradition) and the weakness of the divided civilian parties , if the small but coherent and centrally led Bolsheviks were to be destroyed as an effective force in 1917-19 the military elite rather than the divided and squabbling civilian politicians would be the main effective force in post-war Russia - and the middle-class and urban civilian parties do not have any backing in the vast rural hinterland or the provinces. The urban proletariat in Moscow, Petrograd and a few other major cities might try to rally to the Mensheviks or the Social Revolutionary factions if the Bolsheviks fell, and in OTL the SRs (not the Bolsheviks) had majority support in the late 1917 elected Assembly, but they were too weakly led and incoherent to stand up to a determined and ruthless central regime - be it Bolshevik or military. An urban revolt would probably fail, as per the 'July Days' in 1917 Petrograd.
If the Kornilov military rising secures Petrograd in autumn 1917 rather than being held back by the Bolsheviks helping the Provisional Government survive, then provided that the weakened central army can remain coherent under well-directed leadership allied to the moderates in the PG they stand a chance of holding onto the central parts of Russia into 1918. Particularly if the Bolsheviks then attempt a workers' rising in Petrograd but are swept aside and Lenin and Trotsky are killed or have to flee? And if they signed a Brest Litovsk style treaty with the Germans to secure a truce and sacrificed Ukraine and the Baltic states to Germany, they would logically survive until the November armistice and then be able to rebuild the country. Assuming that the not very 'political' or flexible junta of senior ex-Czarist officers at the top, led by the elderly Kornilov, has to rely on its more capable and younger members like Brusilov and later Admiral Kolchak plus the moderate parties in the neutered Duma, eg the Cadets , in a military-civilian alliance, eventually a 'Putinesque' system of one-party autocracy led by the army and bureaucracy would emerge. Either a cohering of pro-military parties in a 'rigged' parliamentary system relying ultimately on the army would be led by one of the younger centrist politicians who feared the Left more than the Right, eg Miliukov or Struve, or a younger and more flexible military strongman would direct this.
Logically, the best placed person as a long-term leader is Kolchak, as relatively young (born 1879) and a high-reputation national hero of the First WW, but in real life he was not very politically adept, sociable, or good at politics - so how about a more flexible and skilful equivalent emerging from the central ranks of the army in the 1920s? If he stays loyal to the national cause and has not joined the Bolsheviks in 1917-18, the best younger Russian commander who in OTL ended up as a highly-regarded Communicst commander in the 1930s (and was shot by Stalin for his pains) was Tukhachevsky.
If the Civil War sees a more coherent White movement take Moscow in autumn 1919 via the advance from the South (Deniken, if better supported and without a rising to his rear) or take St Petersburg via the smaller but potentially deadly attack from Estonia (Yudenich), possibly aided by an unexpected disaster to the Bolshevik cause (Trotsky's armed train comes off the rails at high speed and kills him?), we have a potential White victory. Then follows the erection of a military-led right-wing 'patriotic' regime in Russia, with various centrist parties from 1917 adhering to it for their own preservation after seeing what the Bolsheviks did to the Assembly in 1917. Possibly a semi-parliamentary regime in the 1920s later turning more authoritarian under the strain of economic and political crises after 1929, as in OTL various Balkan states. Again, we get a respected older military leader from the civil war - or possibly Grand Duke Nicholas Nicholaevich? - as head of state in the 1920s, then a younger general , admiral or civilian front-man. On the parallel of the post-1926 Pilsudski regime in Poland (military led) or an equivalent one-party regime under Salazar in Portugal (civilian led), this could survive until the Second World War - and if there is no 'Bolshevik menace' to fight does Hitler have any reason to attack Russia provided they cannot stop him seizing the independent Ukraine as 'lebensraum' for German settlers? Or can a non-purged, high morale Russian army stop him easier than the Communists did in 1941? Either way we could then have the White Russian one-party nationalist state under its strongman surviving right into the 1950s and 1960s. One man could lead this for 30-odd years, if young enough at the start of his rule.
