In general, I would expect Companion to do the following. Some of the following is subjective, but I think we can agree it's broadly what we might expect.
If a card is available in a regular version, I should be able to see the regular version.
By default, the regular version should be shown, because it's recognisable and the showcase might be less legible, or in Phyrexian, or etc.
If a card is available in alternate treatments, like showcase or extended art or borderless, each of those should be available to view.
For example, if I look for Adeline, Resplendent Cathar in Midnight Hunt, I should be able to see her regular and showcase prints. If I look for Arlinn, the Pack's Hope, I should be able to see her regular, showcase, and borderless treatments.
Companion instead does the following:
If a card has only a regular print, the regular print is shown.
If a card has an alternate treatment, only the alternate treatment is available, and only one of them. You cannot view the regular treatment (in the case of Adeline) or other, different alternate treatments (in the case of Arlinn). They simply aren't present.
Unless it's a transform card, in which case the regular treatment will be shown instead of the back face of the card.
Examples
Arlinn, the Pack's Hope
Arlinn shows, by default, her borderless print. If you hit the transform button to view the other side, you instead get ... Arlinn's regular print.
Transform cards are supposed to instead show you the back face when you hit that button, including its oracle text.
This means Arlinn Kord's back face is simply not available to view on Companion. Neither is her showcase print. This is the only entry for Arlinn, the Pack's Hope on Companion; there isn't anywhere else hidden away to find this information.
Circle of Confinement
Circle of Confinement instead shows up as Van Helsing's Holy Ward (with the Circle of Confinement oracle name). There is no way to view the regular print.
Urabrask, Heretic Praetor
Urabrask shows up in his Phyrexian print exclusively. This is a significant issue for search results legibility.
There is no way to view any other versions of this card, including his showcase.
Transformers (BOT)
All the cards from the Transformers (BOT) set also exhibit this issue. In this set, every card is a double-faced card, and with the sole exception of Arcee, every card also has an alternate Shatterverse version.
Arcee, as you can imagine, is the only card with both the front and back face available.
Blaster, meanwhile, just shows both his front faces, Shatterverse first. Back face data is unavailable for him.
In general, I would expect Companion to do the following. Some of the following is subjective, but I think we can agree it's broadly what we might expect.
For example, if I look for Adeline, Resplendent Cathar in Midnight Hunt, I should be able to see her regular and showcase prints. If I look for Arlinn, the Pack's Hope, I should be able to see her regular, showcase, and borderless treatments.
Companion instead does the following:
Examples
Arlinn, the Pack's Hope
Arlinn shows, by default, her borderless print. If you hit the transform button to view the other side, you instead get ... Arlinn's regular print.
Transform cards are supposed to instead show you the back face when you hit that button, including its oracle text.
This means Arlinn Kord's back face is simply not available to view on Companion. Neither is her showcase print. This is the only entry for Arlinn, the Pack's Hope on Companion; there isn't anywhere else hidden away to find this information.
Circle of Confinement
Circle of Confinement instead shows up as Van Helsing's Holy Ward (with the Circle of Confinement oracle name). There is no way to view the regular print.
Urabrask, Heretic Praetor
Urabrask shows up in his Phyrexian print exclusively. This is a significant issue for search results legibility.
There is no way to view any other versions of this card, including his showcase.
Transformers (BOT)
All the cards from the Transformers (BOT) set also exhibit this issue. In this set, every card is a double-faced card, and with the sole exception of Arcee, every card also has an alternate Shatterverse version.
Arcee, as you can imagine, is the only card with both the front and back face available.
Blaster, meanwhile, just shows both his front faces, Shatterverse first. Back face data is unavailable for him.