Correct, you are not alone - we had a few similar support cases created by other reversed incremental backup mode users already. Reverse incremental is the absolute worst backup mode in terms of both fragmentation and I/O load, I would not use it with ReFS myself - there are no benefits.
Maintenance operation essentially only does "compact" operation which releases the no longer used backup file blocks to the file system, so it still makes great sense to do. As far as defragmentation, it makes no sense on ReFS volumes. Here's my explanation from another topic:
You should treat ReFS volume where block cloning was used as a sort of deduplication storage. You can never have it NOT "heavily fragmented" due to the nature of the process (different files sharing the same physical block). As such, there's absolutely no point to perform defragmentation - just like there's no point in defragmenting a deduplicating storage. In fact, the only way to actually defragment any given file would require "inflating" one by recreating the file without leveraging block cloning.