Just look at who gains and loses from this:

Russia gains:

• Mostly settle a personal score
• Eliminate the minor political threat that Navalny poses while in prison
• Make sure he never plays any part in Russian politics again, in the very slim chance he escapes prison, or is the same person 30 years later (when his imprisonment would end).

West gains:

• The few Russians who supported Navalny might now increase in numbers due to perceived martyrdom
• Nazi and defeatist voices become more prominent in Russian discourse for the coming month, as the discussion turns to Navalny's death
• Rallying cry against Putin
• Make Putin look like a dictator
• Revitalize anti-Russian sentiment and fearmongering (excuse diplomatic actions, military funding, and mishandling of other national affairs)
• Can constantly talk about this in the news for the next 1-2 years
• Revitalize support for Ukraine, which was dangerously waning (with a US election coming up in a few months, and the current president being criticized from everywhere that he spent too much on Ukraine and Israel)
• Turn attention away from condemnation of Israel as a genocide perpetrator by the ICJ (Honestly, this alone is reason enough for Israel to have done it)
• Strengthen NATO by herding more potential members forward

looks that way