Backing up in real time - with synchronization plus RAID 1 or with just only RAID?

[Thy Grand Voidinesss]

Currently I use mix of NVME M.2 drives and SATA SSDs [and offline archival SATA HDDs] on Windows 10. But due to dropping prices of big-enough-for-me drives I decided that I will not carry over to my next Windows [by then 11 or 12] machine my data safety system consisting of spreading it on few physically separate drives. Instead I want to buy some 8TB NVME M.2 model in more than 1 unit and keep all of those drives either directly on my motherboard or in some kind of PCI-e container; or maybe all or some in an external security box [which may not exist for now] connected with a single cable. [My system drive and archival ones will be of separate arrangement that are not to be discussed in this topic, as well as a possible cloud storage]

Thus a question arises: will it be better to use 3 same drives as RAID 1 - or 2 units in RAID 1 plus the 3rd being filled via synchronization method?

With time I might add another drive to that RAID 1, to sleep more soundly - but I would want from get-go to have possibility of just grabbing one of them and flee from a house when fire department wakes me at night or during a day when an air strike happens. Should this removable / mobile drive be synchronized - or could it be just one from the RAID 1 setup, because I also will be able to connect it right away to any other machine after unplugging it from current / main one?

[Thy Grand Voidinesss]

Any thoughts, anyone?

[Thy Grand Voidinesss]

Well?

[void]

My advise:

Avoid USB and have as much redundancy as possible.

If your adding more than 3 drives, consider raid 6 with the appropriate hardware.
Avoid software raid solutions.

[Thy Grand Voidinesss]

My advise:

Avoid USB
[...]

You mean USB storage devices like pendrives?

[void]

Any connection over USB.