Can Valsalva maneuver cause ear blockage or fluid accumulation?

For my own recurring (every 2-3 weeks) ear blockage and hearing loss (diagnosed as otitis media and treated), I have done some search online and saw suggestions to tie valsalva maneuver to the cause of it. In your experience, is this a weak and uncommon reason for ear blockage and swelling? Is it true that keeping your mouth slightly open during Valsalva can help preventing this from happening to the ears?

No, the valsalva maneuver does not cause otitis media.

What if otitis media was a misdiagnosis? If people can burst their blood vessels in the eyes, can the same happen in the ears and cause some swelling or fluid buildup inside? (I know how unscientific that sounds by the way…)

It is possible to rupture the tympanic membrane, yes. This looks differently than otitis media, though.