I can surely state that alchemy tainted Historic format. I do not understand why the decision of mixing format, this is the most stupid idea ever, it does not make the game more interesting, just annoing.
I will ask a question to the WOtC genius that allowed it: would you allow the use of specific legacy cards in modern format? or allow the use of UN- sets in any other format?
this mix and match had unbalanced the game and people like me that like the traditional card game, do not find play with alchemy cards in Historic (that change the text of the original card(blasphemy))playing actually magic, because those are not MTG cards.
if you want to introduce a new format OK
if you want to change the cards text OK
but do not mix these with existing format or "it perpetually become c!£$p"

Alchemy as a format itself isn't a problem, but the fact that Alchemy pervades Historic AND basically every event is absolutely frustrating. One of the biggest reasons I play Arena is because it is *not* Hearthstone, and this takes the very worst part of Hearthstone and shoves it in all areas of the client that I used to enjoy.

Please isolate Alchemy into its own lane and keep it out of events by default. It non-intuitively changes hidden information in ways that you cannot reasonably play around and is very much against the spirit of what makes Magic great in the first place.

If the internal answer is "we can't split Alchemy off without splintering the playerbase", then the answer should be to revert Alchemy until the playerbase is strong enough to survive it.

Players should not have to opt OUT of what is effectively a silver boarder product, Alchemy should 100% have been an opt IN feature. Please fix this as soon as possible.

Can't seem to play historic unless I use the alchemy cards. This makes historic unplayable because it becomes a constantly shifting gameplay where it was supposed to remain the same and standard was supposed to shift.

Won't be playing again till there is a concrete non-changing playstyle

Please remove Alchemy changes from Historic, then keep the two formats separate. We like historic to reflect the actual paper magic game. No need for nerfs or digital-only cards.