Oppose.

He got the top position during a coup ... against the previous group of mods

This is not even a possible explanation. Mods that are on lower rungs cannot "coup" against mods that were there first. The only ways sync could have become top mod are if the people above him deleted their accounts, got shadow-banned, or stepped down.

and has refused to relinquish his power

There is no term limit for any mod. Proposals to remove bad or inactive mods have taken place in the past. This is not the first proposal to suggest that sync step down. Until you have the votes, they are under no obligation to place your judgement on their ability to continue over their own.

he also has a long story of defending abusive users like bourgie liberal and fascist sympathiser /u/min_thamee

Min had a ban reversed by sync when it was undertaken pre-emptively by another mod even though it didn't have the support of the community. Min was later banned when there were enough votes to ban them.

and liberal /r/drama troll /u/prince_kropotkin

Numerous ban threads have been created for PK, and none of them have reached the consensus threshold required to institute a ban.

he also defends zionists and israel sympathisers like /u/Rvannith to the point that Voltairinede resigned their position

There were not enough votes to uphold /u/Rvannith's ban. That's the only reason why it was reversed.

In all three of these cases, your problem is that sync upheld the consensus rules instead of deferring to people who didn't have enough votes to get their way properly. In the case of min, a case was built and the user was eventually banned. In the other cases, that has not happened. The fact that this hasn't been dropped despite an utter dearth of new evidence against either user reflects an unreasonable sense of entitlement and unjustified sense of ownership that you feel over this space. If strong support from the community isn't with you, then you don't get to kick people out just-'cause until it is. You'd be better off creating your own subreddit to get what you're after.

other gems from sync include the demodding of cosmic because she dared, dared to remove abusive people from the sub and create a safe place for the marginalized and banning her entirely when she rightfully protested.

You mean when cosmic acted unilaterally without making ban proposal or transparency threads, or acting in defiance of their results? Or how sync later offered to re-mod cosmic, only to be unable to do so when they managed to get themselves shadowbanned for violating Reddit's sitewide rules against harassment?

the only way to unfuck this community is to demod him and appoint someone who actually knows what the fuck they are doing.

If you think the consensus rules should be changed, propose to change them. The last time someone (me) did that, the community strengthened protections for individuals against hasty bannings. I look forward to reading your reasoned arguments for why this and other such protections should be rolled back.