They need more light;). Cut off all the lanky parts and introduce to more sun slowly. If kept in the same light you cactuses will keep getting the same growth.

Thank you! Do you know if I should just leave the long antenna things to do their thing? Or cut and try to repot those parts as new cacti?

I would cut them off and throw those lanky parts away:).

Once your plant is so etiolated, it will not revert to 'proper' shape/size. That's why Kara is suggesting to dispose of them.

Plants growing like that get very week, and they can't support themselves. Where are they kept? Definitely need much more light. I know you didn't ask about soil, but it looks too fine (and possibly water retentive) for succulents.

First your pots are too tall. You need shorter pots. You also need to use proper cactus potting soil. Read up on cactus care. You are having a drainage problem. If you are watering your plants more than once a month after October it's too much. If you are in a Northern Climate I would look into a Climate Lamp. Your photo shows you just aren't getting enough light. If you have a southern facing window that would be best. Get them outside as early in the spring as you can.

They look like standard pots - about as wide as they are tall - I don´t really see any problem with them. In fact many cacti have quite deep roots. Some of my genuses, Pelecyphora, Ariocarpus, Lophophora have exceptionally deep taproots and I use Long Tom pots to accommodate them.

Is this the same problem?

Yes they need more light.

help should i chop this :(

Where you have them on that shelf top on a wall it's impossible for them to get any sunlight. Chop them up right away, and throw out that spindly growth