Welcome to the forum.
The current methods used to enter bootloader mode are triggered by firmware. But it is low level QMK code, lower level than what anyone changes when customizing their QMK firmware. I believe one or more normal methods of triggering bootloader mode should still work, even if you mess up your attempts at customizing the QMK firmware to your liking. Presuming you don’t touch the low-level code, which few people outside of QMK developers are going to do.
But if you’re really inexperienced I would recommend playing with a RP2040 dev board first. You can get them extremely cheaply. No reason not to.
All RP2040 chips have a BOOT pin.
But I haven’t seen anyone post pictures of the macropad board with the sticker removed to check if it’s broken out to an easy-to-use pad. So you tell us. Or if you remove the sticker and take a good quality picture, I could help locate a pad.
Also, no need to post the same exact thing in two places Framework 16 Macropad seems to ignore the firmware being flashed - #7 by A_Menadue. It’s in the Framework community guidelines, “Don’t cross-post the same thing in multiple topics.”