Clef change within the measure

I have not seen this convention used before, so it must be a specialist niche that requires repetition of the key signature after a clef change. It's certainly not the "normal" way to handle a clef change.

Can you give us an example of a published edition which uses this method?

Haven't seen this being mentioned

I've studied a ton of notated music and I don't think I've ever seen this notation before. Are you sure you re understanding their suggestion correctly? I'm not saying there is never a case in history where this has been done, but surely a professional engraver would know it's not the norm.

Anyhow, MuseScore does actually allow you to insert a mid-measure key change if you want, but unfortunately it is displayed before the clef change and still using the old clef, so it won't help here. You'd need to add the accidental manually as symbols if you want this. But I'd strongly recommend against it, since it is not standard and may confuse readers into thinking there is a key change when there really isn't.