The idea of a sliding window is very important to even out the conditions under which everyone competes. Basically after 1 year everyone has the chance to go through exactly the same circumstances, same contests, same playerbase.
I would still exclude sprints or put them into a different category at least. Have sprints be a different category and not part of the contests.
Without the sliding window and by including all small contests (after you scale the formula to take into account 200 - 500 participant contests) you get a chaotic leaderboard which won’t have as much worth competing in. For example over time the amount of players with 3 contests where they achieved top 10 accumulates and takes away from the motivation to go all in on it. A seasonal ranking however brings everyone closer to a new start, a blank slate and is therefore more encouraging.
Participants who like the 10 days contests don’t necessarily like the few hour contests. Those might also not fit into everyone’s free time and counting them the same way as the 10 day contests only generates chaos, especially if the last 3 contests are to be considered for the contest rank calculation.
Alternatively there could be a seasonal leaderboard. Only what happened during the last selected period of time is displayed. Would very much prefer this as default leaderboard over the “hey someone got #1 in 3 contests that took place a decade ago” while today’s environment is completely different. Completely different competition and challenges. This is also more in favor of those who remain active.