These are the drive cages I used (seems pretty generic, the stand should work with all the other similar cheap cages I've seen on Amazon): https://www.amazon.it/dp/B099JYL5LR

Needed to add HDDs to my mATX case, found some decent 5x HDD cages but didn't know how to “add” them to the small case. Thought about just zip tying them on the top of the case through the ventilation holes but didnt really like the idea.

With this base the cages stay toghether and are a lot more “stable”, the dont move around as much as before. Would recommend adding some rubber feets.

You could just remove the back panel from the case and maybe zip tied the legs to the case so that it can't get away from the case. Since my front panel is plexiglass and I don't really care about it I plan to drill holes in it to pass the cable through the front and maybe bolt or zip tie the cages to the panel, like this I'm sure it's not gonna move and I can keep both panels on the PC :)

I printed it upside down to save on supports, came out great :)