In agreement with mostly all of the 1 star reviews here.
As for the plot, besides being rather ambiguous it was simply just weak from start to finish. All the same alternate timeline, multiverse clichรฉs were used. The antagonists and supporting characters were forgettable and uninteresting.
Character dialogue was forced and for the most part annoying.
The excessive use of profanity does not achieve as much as it could have, had it been used more sparingly.
The special FX were good as per usual but could have been used more effectively to convey a sense of urgency, intensity or any other emotion rather than the mindless and gratuitous violence.
The one liner jokes and overall humor didn't garner more than the ocassional "ha" out of me and seemed like more of a desperate attempt to be relevant only to achieve about as much as a sarcastic teenage remark. Whereas the first two films had me beside myself in laughter and in unspoken/subtle humor.
It was a let down from the first 2 deadpool films, which were great in many aspects. As a film however the third installment was average at best.
In fact from a production company with such a big budget I would say it was below even average.
As a trend I have noticed lazy scriptwriting since Infinity War. Remember, with great power comes great responsibility.
Do better Marvel.
I'll be quiet now.