Boeing has trashed its reputation, previously they were an engineering company which built aircraft that set the standard other manufacturers measured themselves against. The last good aircraft they built was the B777, you rarely heard of any problems with the design and its safety record is exceptional.
Then cost cutting, do it cheaper rather than better, outsource and nice big bonuses for the executives became the new focus. We've seen the results with the B737 MAX and all the B787 issues since its introduction. If Boeing don't get it right with the B777X they will be in a lot of difficulty, there were already problems back in 2019 when a door failed during a stress test and ruptured the fuselage. This type is already facing design issues before quality control comes into question.
The B737 is a corpse warmed up and urgently needs replacing with a clean sheet design to compete with and ideally surpass the A320 and C919. However this will require a lead time of many years and billions of dollars in investment. Get this wrong and the new duopoly will be Airbus and Comac. No one trusts Boeing anymore and if the big operators book out Airbus production and the lead time is too long, it may well persuade other airlines to give the C919 a chance. Whilst the Chinese aircraft isn't yet as capable as the A320, if you don't need extremes of range and payload it could well be suitable. Government back financing with an attractive price and a few discreet "donations" could see it entering the mass market.