Q.cactus identification for repotting compost choice
Could you please tell me what type of cactus is the guy on the far left in the first photo in this link?
https://www.barrythecactus.com/product/mini-cactus-x-3-assorted
or the front one in this link?
https://www.barrythecactus.com/product/pink-boob-pot
I have that mini one and I’ve managed to give it rot. I have just cut off the bottom rotted part and need to choose the appropriate soil to re-pot and try to save it!!! Your site says apparently if it’s a tropical variety you want a bit of peat in the soil if it’s a desert variety you don’t. Thanks!!!

Use a good commercial cactus soil mix for all indoor cactus.
This article will help you.
https://www.gardeningknowhow.com/ornamental/cacti-succulents/scgen/cactus-potting-soil.htm