I have made my own mod, inspired by p0xus' mod, made from 2.2 mechanics. Feel free to go check it out!
https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=1591024851

Okay, I finally had a chance to take a look at what was going on.
I am not sure what 2.2 changed in relation to this mod. I think the issue lies with the planetary rework, specifically the removal of the tile system, as that is what everything was based on, such as resource placement, size, etc. Unfortunately, I have no control over that. All this mod does is change the requirements to build these structures. The base mod adds all of the different Ringworlds, but in a way that they are all free and that in order to build a 12-segment ring, you must first build an 8-segment in the same system. This causes a LOT of unnessesary clutter if you only want a specific ring. This mod removes that pre-requisite requirments as well as adds enables the costs.
I will have to wait for p0xus to update his mod first, so that I can retweak the requirements as nessesary. I hope he ends up just taking my edits and includes them into his mod, making this one obsolete.

Ah, thank you for the reports. I will be looking into it. I will have to figure out what all the 2.2 update changed.

Same its completely bugged for me, i posted pictures in the discussion

Could you update it to 2.2 and use the new alloys instead of the minerals since the original creator is still too busy to update his?

It should be. I haven't actually had a chance to play Stellaris since about the original Distant Stars reveal. I don't thing, though, 2.1 changed anything this mod handles, though. If anyone has had issues, please let me know. I do have another mod I need to update anyway.

2.1.2 compatible correct?

It could be.
I use the 12section and sometimes the 24section rings as a hub of a massive empire. I am trying to figure out a way to "gift" planets to allies that they then colonize. My plan is to use one of these large rings as a multi-cultural hub for a massive multi-species empire/federation...

lol a ringworld for noobs who fear to leave their system

Too op?
I think it is actually less op. Now, each RingWorld cost the same as vanilla, when they are usually free, and take tears to build, when they are usually instant-build.
I can easily raise the cost and build time, but the base mod had it vanilla, this simy enables those costs.
If anyone has any suggestions for new costs and build times, I am happy to change it.

ya no thank to op