Not that I know of
Can 4 player/variants be on mobile

chess.com/variants is separate from chess.com/play, thus, different teams work on the two and they are hard to combine. In addition, the 4 Player Chess board and its pieces are extremely hard to control, given how big it is and how small phones are.

You can play 4pc/variants on the mobile app if you click on a club match in your messages. The sidebar will become like the browser version.

Not only is variants separate code and developers, the mobile apps are separate code and developers. Along with the screen size issues, my guess is it's unlikely to happen.

but it is very hard to play variants on mobile app(due to the nature of small screen of our phone)
yeah my method works better on a tablet

It’s not hard tho
You've clearly overestimated how easy programming is then...
It is u who underestimate the hardness of programming......
Reread my sentence, it’s weird but not the definition that you interpreted it as…

Here is link for most popular 4 variant physical chess set. https://www.chesshouse.com/collections/3-and-4-player-chess-sets/products/large-4-player-chess-set
If you have local chess club then money worth. Or simply ask your friends/family to play on the laptop, which will work. If you don't have club then I will suggest you to not spend on physical board. For family, It's rare to convince 3 others unless they are chess savvy if not 2 or 3 game max then board will stay in garage forever. Bitter truth!
Good luck!

Its not hard to play variants on mobile chess + its possible.
Sure, it’s not hard to get on Safari and then go to Variants. To code the function to access it within the app, transfer all of the image files, recreate the layouts, takes a lot of time for something that (unfortunately) isn’t top priority for chess.com.
It would be nice when you want to play with family