I’d go with a wago box, or any other maintenance free junction box.
The minor issue is that you’re unlikely to have the tools or equipment to be able to check that your repair is ok - if done properly it will very likely be fine, but just a heads up.
I just chopped through a ring main (not wired up to the CU yet, so no shower of sparks and death).
Am I ok to connect it back up using terminal blocks (I have a bunch which I think are 30A) and put that inside a connection box?
Or is this sort of thing notifiable?