Russian railway improvements will shorten mobilization times, and provide commercial benefit.
Russia had a good aviation industry, and due to the nature of the country (huge), a commercial need too, so I expect the Russians to lead in aviation.
Russian navy will be large and modern, will totally own the Black Sea.
Diesel tech will quickly make submarines rangy and big, people will think of possible uses for them, stealthy offensive mine layers if nothing else.
Commercial tech won't be slowed by the war, air conditioning, refrigeration, commercial radio, commercial vehicle, agricultural tractor use greater than 1920 OTL.
The powers will continue to sink money into colonial infrastructure, more of that than OTL 1920, Germany for example will have railways to Lake Victoria and Lake Chad.
Berlin to Baghdad railway will be completed.
Countries without much oil like Germany are going to look for sources.
Ottoman empire areas like Armenia and Kurdistan will continue to be restive. Ottomans will have more problems than anybody still with minorities.
Alliances:
Russia with a rebuilt Navy and better transportation infrastructure will be threatening to Britain. But maybe not enough to change the Alliance system.
Germany will have to be more cautious, West first war plans are not going to work, war planning will have to consider a long war.
Sweden and Romania might be brought into the German alliance system if Russia threatens.
Austria will be just fine still in 1920. Germans/Hungarians/Poles are fine with current state of things. Command language/monarchy system will tie her to Germany still.
I could see Germany getting really aggressive toward Belgian and Portuguese colonies.
War in 1920 could be some stupid thing in the Balkans, or Russia might try to "liberate" Armenia from Turkey, and trigger events that way.