Recently got a M1 Mac Mini, a little late to the party but I got it as a 2nd hand with a good price. Been testing out a couple of things but as far as desktop variant of the Mac, unless you have unlimited money, focus on the RAM and not the storage.
Reason being, you can always boot externally, but RAM is pretty much not upgradable.
The options available for external boot can goes starts from a entry level sata ssd with usb enclosure to higher end nvme with thunderbolt enclosure, either way they are both cheaper than Apple native ones. Currently I am using a Corsair MP600 booting externally using a Chinese 10Gbps enclosure.
If somehow a fresh install does not boot or fail to boot, do try to reinstall again or a few times. You might also want to try out performing the fresh install with 5Gbps USB-A first before swapping to 10Gbps later if it somehow does not work for you.