How to identify SMT transitors
Identifying SMD components is usually not possible. Markings, if present, rarely refer to what's inside the package. That is done because there is no room for useless information, and because printing them rises costs. Only "big" resistors, as 1206, are usually marked.

That said your best shot is to desolder one of the working one, find out if it's a fet or a bjt, then understand if it's a p or a n device testing it with very low voltages to avoid breaking it, then hope it's not some special very low noise, very high frequency, very whatever device, maybe having a guess at what it's doing on the board, buy a replacement and throw it in.

If there are several of them they are probably standard small signal transistors, some 100mA of collector/drain current, 100-ish hfe, 1-2V threshold voltage... But that's a wild guess.

Knowing what the board is supposed to do can help a lot.