The first step to improving the code is understanding the situation, ideally to find a reproducible case. Typically the next step is hard too – finding someone willing and able to code a fix for a rare problem. Duplicati has many more issues on record than there are developers, so prioritization has to be done.
Database repair fails, recommends repair to fix, so this goes in circles? #4923 is yours with this topic.
Seeing this bug report might suggest what sort of problem in the dlist or dindex files could cause that. Confirmation could be obtained by looking in the file, but one challenge is that a dlist file could be big, meaning hard to fit into an editor without exhausting memory. Another challenge is that it’s a long line.
Thanks for helping push it one step further.