If the rate of crash continue then there will be no Air Force for Bangladesh. There will two Air Forces surrounding Bangladesh those are Indian and Myanmar.
Talks are underway for India to procure F-35 after India has been excluded from CAATSA Act and withdrawal of Su-57 program.
Myanmar will have advanced Fighter Jets soon. Talks are underway with a partner nation to procure fighter jet advanced than Su-30 which Myanmar ordered.
As far as Bangladesh concern, they will always be like the below link.
https://exoatmospheric.wordpress.com/2018/04/13/bangladesh-air-force-a-flying-club-of-bangladesh/