Samsung a7 2018 sm-750fn Stuck and several problem

[Denversmartphone]

Hello dear, i have a problem with a Samsung a7 2018 from my friend..so i explane the problem..the phone doesnt work with any sim card..my friend give a mobile to a Person that i do know WTF do block the phone and appears a Red write on boot where Say that smartphone Will not work without originale firmare..so i try to repair with Odin..i flash thousan of Rom Italian on the beginning all still working but not the Sim..It recognize inside but i can select the network so i can only make emergency call..i try to flash with different rom with custom rom with twrp but nothing Always the same problem..i try different rom all firmware flash correct with Odin but now i face a new problem..when i flash with all firmware i use It flash correctly i can go in download mode rescue mode but i cant procede with smartphone configuration..Is still Always lock on Samsung logo..and stay like this for ever..any help for fix It please? The latest rom installed Is android 10 firmware itv..model Is sm-750fn..if i go to download mode It happears avoid waranty 1 and carrier_id omn..now i cant install in any Way twrp again..Always file and Say that only original bootloader Will work