Abstractions are useful to make a box and put horrors of edge case handling or business requirements variability in it :) But if there are little of those, no

Abstractions are useful to make a box and put horrors of edge case handling or business requirements variability in it :) But if there are little of those, no need to make them prematurely. Field mapping is something for EF Core mapper configuration or repository implementation to worry about, no need to do the job twice. You often don't need separate "Host" and "Core" projects either. And if you ever need to migrate to a new hosting solution, it happens maybe once during application lifecycle, and even then it requires some effort. Replace-all and IDE tools work just as fine if not better for this, no need to inflict easily avoidable pain simply because it looks consistent with "other" solutions that were written 10 years ago.