in inset feed after matching patch antenna impedance is matched to 50Ω stripline.
does it have any significance on the length of 50Ω strip line or it can be of any length
i am new to design and planning to use λ/4 transformers for splitting feed(two T junction splitters)
looks like you are designing wilkinson power splitter. in that case, impedance goes from 50ohm to 70.7ohm (spliting arms) and back to 50ohm. the spiltting arms (70.7ohm) have to be quarter wave length but 50ohm line length is negligible.