macbook pro – 4k external monitor stuck in 1080p

I have Macbook Pro 16″ 2019 model. Recently I bought Acer 4k Monitor VG280K.

I’m connecting it to Macbook Pro with HDMI which came with it and attached it with a USB C to HDMI converter which support 4k@60Hz.

I’m facing a very annoying bug. Sometimes randomly Macbook is rendering full 4k and sometimes its rendering only 1080p. I have to restart or replug the cable multiple times for it to render 4k.

I noticed others are also facing the same issue https://piunikaweb.com/2021/02/04/external-4k-monitor-issues-after-macos-big-sur-11-1-update/

I have talked with the Apple Customer Care but they were not helpful.

I’m also using this new monitor with Windows laptop and getting full resolution without a break, so the HDMI cable and monitor is fine.

Thousands of people like me are facing the same issue as mentioned here https://discussions.apple.com/thread/252174979

I patiently waited for 11.3.1 update and hoped it might fix it but it didn’t fix it. I don’t know what to do now. I’m stuck with this problem for months.