"To put it simply, this job isn’t working for me," 46-year-old Ortiz said Tuesday night during a City Council meeting.

Ortiz has formally resigned, effective immediately.

During the meeting, he explained his decision -- saying he could no longer handle the "hostility and judgment" he faced on a daily basis ... adding he felt he was a target for "character assassination each and every week."

"I ran for this position with hopes to better my community, work on my constituents and give them a voice, making our beautiful city safe and clean and to ensure a bright future for my children,” Ortiz said.

"I was under a notion that I was in a bipartisan position and that we all had a common goal that our city and our constituents could have."

"As of recent, the attacks against me have moved to involve my family. I now feel that their safety is in danger."

Ortiz -- one of the greatest UFC fighters of all time -- won a City Council seat back in November, after receiving support from the Trump family.

During his campaign, Ortiz championed Trump's positions on things like border security, immigration, law enforcement and more.

But, since his first day in office, Tito had been under fire from other politicians and city officials who say he refused to follow COVID protocols and even got in a screaming match with a citizen.

And, just last month, Ortiz found himself in hot water for allegedly filing for unemployment against the City of Huntington Beach ... despite still drawing a full monthly check. Ortiz has denied wrongdoing.