Russia has historically had interests in the Balkans, given the region's strategic importance and cultural, religious, and historical ties. During times of tension or conflict, major powers like Russia may have incentives to exert influence in the area.
With the attention diverted due to the current Israel-Palestine conflict, even though Russia may increase its pace of advancement in Ukraine, the possibility of this war spilling over to the Balkans before the end of 2024 is quite low. The USA will maintain a strong presence in the region to ensure the stability it has achieved and to prevent Balkan countries, which are its military and trade partners, from falling into the hands of their historical enemy Russia. Additionally, US is safety guarantor for all EU countries including EU and NATO candidates. US expenditures on Ukraine shows the importance of the region.

However, energy dependency of some Balkan countries and strong trade relationship between Russia and some of the Balkan countries might affect the course of events.
Natural gas has a share of 11.7 and 12.5% of the energy supply in North Macedonia and Serbia, respectively. The former imports 97.5% and the latter imports 92.3% of their gas from Russia. Montenegro and Kosovo do not need gas for their energy supply, according to the statistics of the International Energy Agency.

As a conclusion probability is low for short term due to existence of the US in the region.
https://www.iea.org/reports/national-reliance-on-russian-fossil-fuel-imports/which-countries-are-most-reliant-on-russian-energy

https://www.iea.org/commentaries/accelerating-energy-diversification-in-central-and-eastern-europe

https://www.cfr.org/article/how-much-aid-has-us-sent-ukraine-here-are-six-charts

https://www.gisreportsonline.com/r/balkans-military/

https://www.swp-berlin.org/10.18449/2023C36/

Economic Relations between the Western Balkans and Non-EU Countries

How the EU can respond to challenges concerning direct investment, trade and energy security