Having stated my stance, I would say the best way to accomplish what you want is to create a Buff that all MP players start with, which lasts through death/respawn. Let's call it the "Blood Moon Plague", which turns you into a zombie after 8 days, if untreated.
But the buff lasts 8 days of playtime for each player? Or ingame time?
Regulary bloodmoon every sunday is a game mechanic, that is completely incompatible with multiplayer on open servers. So assuming game time is always running, because there is at least one player online every time and the server is using standard 60min days, a bloodmoon will happen every 7 hours. So e.g. bloodmoon on one day will happen at 19pm and you come home from work and start playing at 18:30. What do you do if you have nothing prepared because you haven't had time to play since your last bloodmoon?
Next bloodmoon is at 2am, but you have to quit at 1am, because you have to go to work next day. Did you skip the bloodmoon intentionally and need to be punished for that?
Next bloodmoon happens at 9am. You just log on quickly at 8am before going to work, just to put stuff in your forge and workbench and log off again. Did you again skip the bloodmoon intentionally?
Next bloodmoon than happens at 16pm but you just come home from work at 17pm. You just missed bloodmoon...
So yeah, it's easy to intentionally avoid a bloodmoon that way, but there are various other reasons why you can't play a bloodmoon.
If you want to have "global events" that affect all players at the same time in a multiplayer game, you ALWAYS encounter the problem, that player simply log off if they are not interested in the event and nobody can force them to attend the event.
If you are introducing buffs for played bloodmoons like 2 attribute points, you are basically nerfing every player that doesn't have time to play 24/7. In the above setting you have ~3 BMs per day, that makes 6 missed attribute points for every player that can't play on day!
The "problem" also occurs on smaller servers and also is the reason why we stopped playing the game in larger groups (>4 players). Either you only play if every participant has time to play, which (for us) results in only being able to play 2-3h per week, or you continue playing without the full group which leads to players getting decoupled. Most times these people stop playing completely as the game progresses because it isn't really fun playing with people that are 30 levels ahead and with that massively pushing gamestage.
That is also the reason, why i am completely NOT interested in playing on larger public servers. I'd probably do if bloodmoon is turned off and difficulty increased in other ways.