What is the maximum take off climb angle of a Boeing 737 MAX?
That’s a wild demonstration but it’s also not a very realistic  barometer performance for typical 737 operations. The video you see there is a high-performance demonstration flown in an air show or a trade show just for the purposes of entertainment. It involves an airplane that has literally been stripped down of any unnecessary parts, no other personnel or cargo on board except for the minimum required flight crew and barely enough gas to get the performance done and maintain day VFR reserve minimums to get them back to the airport.   The climb there was done in about an angle of 50 to 55° from the horizontal.    Even in these conditions a Boeing 737 does not have a thrust to weight ratio exceeding one and as such the aircraft is in fact slowing down. Still it gives an impressive climb to around 2000 to 3000 feet above the airport for the spectators below.