Custom SAMD21E18A board

Hi,

i have a personal board build with an samd21e18a, I would like to create the board in Platformio, I found this example for a samd21e17a here, I have already my variant files etc for my board.

But I have some question, first do you think I can start with this template for my samd21e18a? In my case I used a bootloader but in samd21e17a example No ldscript are specify,

"arduino": {
       "ldscript": "flash_without_bootloader.ld"
},

Should I put mine here? Because in my previous configuration for Arduino Ide, I have these lines :

my_board.build.ldscript=linker_scripts/gcc/flash_with_bootloader.ld
my_board.bootloader.file=zephyr/sam_ba_Generic_x21E_SAMD21E18A.bin

And this line replace extra_flags example?
my_board.build.extra_flags=-D__SAMD21E18A__ {build.usb_flags}

What do you think? Or maybe somewhere samd21e18a template exist?