I have voted for a number of different parties - mostly centre or left, but have voted Tory in my past on occasion where I considered that candidate was the best option .
The trajectory of the Conservatives post 2015 and certainly post Johnson means I cannot imagine considering a Tory vote again. I may be becoming older and more grumpy but a party that felt Johnson was the right person would need a lot of rehabilitation to get my vote.
Interestingly, I am good friends with dyed-in-the-wool Tories who feel utterly at sea currently. One has moved over to Starmer's Labour, one is utterly undecided and another one, in quite a move, has gone over to the Greens and become very environmentally aware. All three have made far more monumental changes in their political outlook than me, probably on a similar scale to those Red Wall voters changing lifetime allegiances to Johnson at the last election.
I would say changing political allegiance at the moment is far more common than previously. It isn't just voters changing their minds in the face of big domestic and international changes but the parties themselves shifting political outlook in a big way as well.