Update in case anyone cares/finds these posts by searching in the future: I've replaced the Veloflex Corsa 28 with Michelin Power Road 28 and one thing became very clear: the Corsas are an awful lot smaller than the Michelin, and possibly than most 28 tyres, both in width (the Michelins wouldn't even get past the open calipers when inflated) but especially in height.
Now I didn't get any issues with the rear tyre and that was fitted with a Schwalbe 18-28 inner tube, while the two tubes which blew out were Lifeline 28-32 and way bigger in size.
Long story short: chances are a 25mm rated tube would work absolutely fine and those Lifelines were a bit too big despite technically being the correct size. The Veloflex were always very easy to fit and it stands to reason also a little easier to pop out if pushed.
That said, the Michelin were an absolute pig to mount, so they're staying on for the time being, but I might give the Corsas another shot later in time with much smaller inner tubes which won't want to bunch up and/or push the bead out.