As stated in the title the mod uses an older version of conventional tags.
For example the #collections/mountains tag references #c:mountain and #c:mountain_peak.
Which has have been replaced with #c:is_mountain and #is_mountain/peak.

For a full list of then Fabric version of conventional tags v2 here is a link: /v2/ConventionalBiomeTags.java
As for Neo, from my knowledge conventional tags are similar across both loader so adding the new tags should also work on neo. But I may be wrong on this.

Well I'll be, i must had missed updating this mod. no idea how and I am upset at myself for it. I could've sworn I did go through and updated the tags at some point unless it was overwritten

I’m the one who PR’d the convention tags to neoforge and fabric. I’ll go through again but generally repurposed structures does use the new tags. I may had missed a few